tag:theconversation.com,2011:/global/topics/testosterone-564/articlesTestosterone – The Conversation2019-09-09T16:16:14Ztag:theconversation.com,2011:article/1228722019-09-09T16:16:14Z2019-09-09T16:16:14ZDoes extra testosterone reduce your empathy?<figure><img src="https://images.theconversation.com/files/291337/original/file-20190906-175705-hcx8as.jpg?ixlib=rb-1.1.0&amp;q=45&amp;auto=format&amp;w=496&amp;fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><a class="source" href="https://www.shutterstock.com/download/confirm/509354542?src=-1-0&amp;size=medium_jpg">Marc Bruxelle/Shutterstock</a></span></figcaption></figure><p>Cognitive empathy is the ability to recognise what another person is thinking or feeling, and one way it can be assessed in the lab is by using the “<a href="https://depts.washington.edu/uwcssc/sites/default/files/hw00/d40/uwcssc/sites/default/files/Mind%20in%20the%20Eyes%20Scale_0.pdf">reading the mind in the eyes test</a>” – or “eyes test”, for short. This involves looking at photos of a person’s eyes and picking which word best describes what the person in the photo is thinking or feeling.</p>
<p>Many studies, including our own, have shown a link between elevated testosterone and reduced cognitive empathy. But a <a href="https://royalsocietypublishing.org/doi/pdf/10.1098/rspb.2019.1062">new study</a> led by Amos Nadler, a visiting professor of economics at the University of Toronto, found that administering testosterone to men does not reduce their empathy, as measured by this test. </p>
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<img alt="" src="https://images.theconversation.com/files/291245/original/file-20190906-175673-1hd5s76.png?ixlib=rb-1.1.0&amp;q=45&amp;auto=format&amp;w=754&amp;fit=clip" srcset="https://images.theconversation.com/files/291245/original/file-20190906-175673-1hd5s76.png?ixlib=rb-1.1.0&amp;q=45&amp;auto=format&amp;w=600&amp;h=361&amp;fit=crop&amp;dpr=1 600w, https://images.theconversation.com/files/291245/original/file-20190906-175673-1hd5s76.png?ixlib=rb-1.1.0&amp;q=30&amp;auto=format&amp;w=600&amp;h=361&amp;fit=crop&amp;dpr=2 1200w, https://images.theconversation.com/files/291245/original/file-20190906-175673-1hd5s76.png?ixlib=rb-1.1.0&amp;q=15&amp;auto=format&amp;w=600&amp;h=361&amp;fit=crop&amp;dpr=3 1800w, https://images.theconversation.com/files/291245/original/file-20190906-175673-1hd5s76.png?ixlib=rb-1.1.0&amp;q=45&amp;auto=format&amp;w=754&amp;h=453&amp;fit=crop&amp;dpr=1 754w, https://images.theconversation.com/files/291245/original/file-20190906-175673-1hd5s76.png?ixlib=rb-1.1.0&amp;q=30&amp;auto=format&amp;w=754&amp;h=453&amp;fit=crop&amp;dpr=2 1508w, https://images.theconversation.com/files/291245/original/file-20190906-175673-1hd5s76.png?ixlib=rb-1.1.0&amp;q=15&amp;auto=format&amp;w=754&amp;h=453&amp;fit=crop&amp;dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
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<span class="caption">Reading the mind in the eyes test.</span>
<span class="attribution"><span class="license">Author provided</span></span>
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<p>Nadler and colleagues also measured digit ratio. The ratio between the length of a person’s index and ring finger is thought to be an indicator of how much testosterone they were exposed to in the womb (prenatal testosterone levels), and <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3044405/">has also been tied</a> to a lack of empathy. Nadler and colleagues’ study found that digit ratios were not related to empathy scores.</p>
<p>From these findings, they draw two conclusions: first, that this disproves a <a href="https://www.pnas.org/content/108/8/3448">previous study</a> by Jack van Honk and colleagues in which administering testosterone to women reduced their empathy. And second, that prenatal testosterone levels do not affect later empathy.</p>
<h2>Challenging the conclusions</h2>
<p>We would challenge both these conclusions, on two grounds. First, Nadler’s study only included men whereas van Honk’s study only included women. So while we agree that administering extra testosterone to men does not appear to reduce their empathy, Nadler’s study cannot be regarded as an attempt at replicating the van Honk study. A large-scale study of women would be needed for that.</p>
<p>And perhaps giving women extra testosterone does reduce their empathy (as van Honk found) while giving men extra testosterone does not. This could be because women on average score higher on the eyes test than men do, so there is more room for their scores to decrease. Also, on average, women have lower circulating testosterone levels than men, so large changes in their testosterone levels may have bigger effects on empathy. </p>
<p>In Nadler’s study, the testosterone levels of male participants were elevated two or threefold. In contrast, in the van Honk study, the testosterone levels of female participants were elevated at least tenfold. It is possible, then, that a higher dose of testosterone <em>would</em> have affected empathy in men. </p>
<p>Second, digit ratio may not be a good proxy of how much testosterone someone was exposed to in the womb, as <a href="https://www.ncbi.nlm.nih.gov/pubmed/15113628">other factors</a> may affect this ratio. To properly study prenatal testosterone, it should be measured directly, using prenatal samples.</p>
<p>Of course, measuring prenatal hormone levels in the womb is very difficult, but it is essential because testosterone exerts many of its programming effects during a critical time window when the brain is developing. </p>
<p>That is why we measured prenatal testosterone levels in the amniotic fluid surrounding the developing foetus in women who opted to have an <a href="https://www.nhs.uk/conditions/amniocentesis/">amniocentesis</a> during pregnancy and then following up the child years later to see how they developed. We <a href="https://www.ncbi.nlm.nih.gov/pubmed/18633782">confirmed</a> that the higher the level of prenatal testosterone, the lower their scores on the eyes test of empathy when tested at age six to eight years.</p>
<h2>Extreme male brain</h2>
<p>In their <a href="https://penntoday.upenn.edu/news/largest-study-its-kind-no-evidence-testosterone-reduces-cognitive-empathy">press release</a>, Nadler and colleagues argue that their new data challenges the “extreme male brain” (EMB) theory of autism. But Nadler’s study has little to do with the EMB theory. </p>
<p>The EMB theory makes no predictions about what will happen to a person’s empathy if you give them more testosterone. The EMB theory simply states that, on tests of empathy, typical females will on average score higher than typical males, and autistic people will on average score lower than typical males. </p>
<p>The EMB theory also states that on tests of systemising – the drive to analyse or construct systems in terms of rules – typical males will on average score higher than typical females, and that autistic people will on average score higher than typical males. </p>
<p>The EMB theory was recently confirmed in the largest test of sex differences in empathy and systemising among 600,000 people, and in the <a href="https://www.pnas.org/content/115/48/12152">largest study of autism</a>, among 36,000 autistic people. </p>
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Read more:
<a href="http://theconversation.com/extreme-male-brain-theory-of-autism-confirmed-in-large-new-study-and-no-it-doesnt-mean-autistic-people-lack-empathy-or-are-more-male-106800">Extreme male brain theory of autism confirmed in large new study – and no, it doesn't mean autistic people lack empathy or are more 'male'</a>
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<p>And in other recent studies, we showed that several prenatal sex steroid hormones, such as testosterone and oestrogen, are elevated in the <a href="https://www.nature.com/articles/s41380-019-0454-9">amniotic fluid of autistic boys</a>, demonstrating the importance of prenatal sex steroid hormones in changing brain development.</p>
<p>So, while the Nadler study is impressive for its scale, we now need a direct replication study of testosterone effects on women’s cognitive empathy. Finally, it is important to separately study the effects of testosterone on the prenatal brain, compared to the effects of the same hormone on the adult brain.</p><img src="https://counter.theconversation.com/content/122872/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>The authors do not work for, consult, own shares in or receive funding from any company or organization that would benefit from this article, and have disclosed no relevant affiliations beyond their academic appointment.</span></em></p>The link between testosterone and empathy is complicated. We don't have all the answers yet.Simon Baron-Cohen, Professor of Developmental Psychopathology, University of CambridgeAlexandros Tsompanidis, PhD Candidate in Autism, University of CambridgeRichard Bethlehem, Research Associate in Autism, University of CambridgeTanya Procyshyn, Doctoral Scientist, Autism Research Centre, University of CambridgeLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1227642019-09-03T13:40:36Z2019-09-03T13:40:36ZStop calling it a choice: Biological factors drive homosexuality<figure><img src="https://images.theconversation.com/files/290563/original/file-20190902-175705-15kuqu2.jpg?ixlib=rb-1.1.0&amp;q=45&amp;auto=format&amp;w=496&amp;fit=clip" /><figcaption><span class="caption">Biological factors shape sexual preference.</span> <span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/lgbt-lesbian-couple-moments-happiness-concept-575079754?src=-1-53">Rawpixel.com/SHutterstock.com</a></span></figcaption></figure><p><a href="https://doi.org/10.1126/science.aat7693">Across cultures, 2% to 10% of people report having same-sex relations</a>. In the U.S., <a href="https://www.statista.com/topics/1249/homosexuality/">1% to 2.2% of women and men</a>, respectively, identify as gay. Despite these numbers, <a href="https://www.pewresearch.org/global/2013/06/04/the-global-divide-on-homosexuality/">many people still consider homosexual behavior to be an anomalous choice</a>. However, biologists have <a href="https://us.macmillan.com/books/9780312253776">documented homosexual behavior in more than 450 species</a>, arguing that same-sex behavior is not an unnatural choice, and may in fact play a vital role within populations.</p>
<p>In <a href="https://doi.org/10.1126/science.aat7693">a recent issue of Science magazine</a>, geneticist Andrea Ganna at the Broad Institute of MIT and Harvard, and colleagues, describe the largest survey to date for genes associated with same-sex behavior. By analyzing the DNA of nearly half a million people from the U.S. and the U.K., they concluded that genes account for between 8% and 25% of same-sex behavior. </p>
<p><a href="https://www.nature.com/news/sex-redefined-1.16943">Numerous studies have established that sex is not just male or female</a>. Rather, it is a continuum that emerges from a person’s genetic makeup. Nonetheless, misconceptions persist that same-sex attraction is a choice that warrants condemnation or <a href="https://www.apa.org/pi/lgbt/resources/just-the-facts">conversion</a>, and leads to discrimination and persecution.</p>
<p><a href="https://wjsulliv.wixsite.com/sullivanlab">I am a molecular biologist</a> and am interested in this new study as it further illuminates the genetic contribution to human behavior. As the author of the book, <a href="https://www.penguinrandomhouse.com/books/608709/pleased-to-meet-me-by-bill-sullivan/9781426220555/">“Pleased to Meet Me: Genes, Germs, and the Curious Forces That Make Us Who We Are,”</a> I have done extensive research into the biological forces that conspire to shape human personality and behavior, including the factors influencing sexual attraction.</p>
<h2>The hunt for ‘gay genes’</h2>
<p>The new finding is consistent with multiple earlier studies of twins that indicated same-sex attraction is a heritable trait.</p>
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<img alt="" src="https://images.theconversation.com/files/290580/original/file-20190902-175663-baya3w.jpg?ixlib=rb-1.1.0&amp;q=45&amp;auto=format&amp;w=237&amp;fit=clip" srcset="https://images.theconversation.com/files/290580/original/file-20190902-175663-baya3w.jpg?ixlib=rb-1.1.0&amp;q=45&amp;auto=format&amp;w=600&amp;h=1200&amp;fit=crop&amp;dpr=1 600w, https://images.theconversation.com/files/290580/original/file-20190902-175663-baya3w.jpg?ixlib=rb-1.1.0&amp;q=30&amp;auto=format&amp;w=600&amp;h=1200&amp;fit=crop&amp;dpr=2 1200w, https://images.theconversation.com/files/290580/original/file-20190902-175663-baya3w.jpg?ixlib=rb-1.1.0&amp;q=15&amp;auto=format&amp;w=600&amp;h=1200&amp;fit=crop&amp;dpr=3 1800w, https://images.theconversation.com/files/290580/original/file-20190902-175663-baya3w.jpg?ixlib=rb-1.1.0&amp;q=45&amp;auto=format&amp;w=754&amp;h=1508&amp;fit=crop&amp;dpr=1 754w, https://images.theconversation.com/files/290580/original/file-20190902-175663-baya3w.jpg?ixlib=rb-1.1.0&amp;q=30&amp;auto=format&amp;w=754&amp;h=1508&amp;fit=crop&amp;dpr=2 1508w, https://images.theconversation.com/files/290580/original/file-20190902-175663-baya3w.jpg?ixlib=rb-1.1.0&amp;q=15&amp;auto=format&amp;w=754&amp;h=1508&amp;fit=crop&amp;dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
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<span class="caption">A new study suggests that genes are responsible for between 8% and 25% of same-sex preference.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-illustration/dna-multi-color-isolated-on-white-717211195?src=-1-47">Guru 3D</a></span>
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<p>The new study is the latest in a hunt for “gay genes” that began in 1993, when Dean Hamer <a href="https://doi.org/10.1126/science.8332896">linked male homosexuality to a section of the X chromosome</a>. As the ease and affordability of genome sequencing increased, additional gene candidates have emerged with potential links to homosexual behavior. So-called <a href="https://doi.org/10.1038/s41598-017-15736-4">genome-wide association studies identified a gene called <em>SLITRK6</em></a>, which is active in a brain region called the diencephalon that differs in size between people who are homosexual or heterosexual.</p>
<p>Genetic studies in mice have uncovered additional gene candidates that could influence sexual preference. A 2010 study <a href="https://doi.org/10.1186/1471-2156-11-62">linked sexual preference to a gene called fucose mutarotase</a>. When the gene was deleted in female mice, they were attracted to female odors and preferred to mount females rather than males. </p>
<p>Other studies have shown that <a href="https://doi.org/10.1038/nature06089">disruption of a gene called <em>TRPC2</em></a> can cause female mice to act like males. <a href="https://doi.org/10.1126/science.1069259">Male mice lacking <em>TRPC2</em></a> no longer display male-male aggression, and they initiate sexual behaviors toward both males and females. Expressed in the brain, <em>TRPC2</em> functions in the recognition of pheromones, chemicals that are released by one member of a species to elicit a response in another.</p>
<p>With multiple gene candidates being linked to homosexuality, it seemed highly unlikely that a single “gay” gene exists. This idea is further supported by <a href="https://doi.org/10.1126/science.aat7693">the new study</a>, which identified five new genetic loci (fixed positions on chromosomes) correlating with same-sex activity: two that appeared in men and women, two only in men, and one only in women.</p>
<h2>How might these genes influence same-sex behavior?</h2>
<p>I find it intriguing that some of the genes from men identified in Ganna’s study are associated with olfactory systems, a finding that has parallels to the work in mice. Ganna’s group found other gene variants that may be linked with sex hormone regulation, which other scientists have previously suggested plays a large role in shaping the brain in ways that influence sexual behavior. </p>
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<img alt="" src="https://images.theconversation.com/files/290575/original/file-20190902-175691-1l5i9pk.jpg?ixlib=rb-1.1.0&amp;q=45&amp;auto=format&amp;w=237&amp;fit=clip" srcset="https://images.theconversation.com/files/290575/original/file-20190902-175691-1l5i9pk.jpg?ixlib=rb-1.1.0&amp;q=45&amp;auto=format&amp;w=600&amp;h=846&amp;fit=crop&amp;dpr=1 600w, https://images.theconversation.com/files/290575/original/file-20190902-175691-1l5i9pk.jpg?ixlib=rb-1.1.0&amp;q=30&amp;auto=format&amp;w=600&amp;h=846&amp;fit=crop&amp;dpr=2 1200w, https://images.theconversation.com/files/290575/original/file-20190902-175691-1l5i9pk.jpg?ixlib=rb-1.1.0&amp;q=15&amp;auto=format&amp;w=600&amp;h=846&amp;fit=crop&amp;dpr=3 1800w, https://images.theconversation.com/files/290575/original/file-20190902-175691-1l5i9pk.jpg?ixlib=rb-1.1.0&amp;q=45&amp;auto=format&amp;w=754&amp;h=1063&amp;fit=crop&amp;dpr=1 754w, https://images.theconversation.com/files/290575/original/file-20190902-175691-1l5i9pk.jpg?ixlib=rb-1.1.0&amp;q=30&amp;auto=format&amp;w=754&amp;h=1063&amp;fit=crop&amp;dpr=2 1508w, https://images.theconversation.com/files/290575/original/file-20190902-175691-1l5i9pk.jpg?ixlib=rb-1.1.0&amp;q=15&amp;auto=format&amp;w=754&amp;h=1063&amp;fit=crop&amp;dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
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<span class="caption">Conditions in the uterus during pregnancy are thought to influence the sexual preferences of the child.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/beautiful-pregnant-woman-shopping-bags-outdoors-503149633?src=-1-18">Anna Om/Shutterstock.com</a></span>
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<p>Males with a genetic condition called <a href="https://ghr.nlm.nih.gov/condition/androgen-insensitivity-syndrome">androgen insensitivity syndrome</a> can develop female genitalia and are usually brought up as girls, despite being genetically male – with an X and Y chromosome – and they are attracted to men. This suggests that testosterone is needed to “masculinize” a prenatal brain; if that doesn’t happen, the child will grow up to desire men. </p>
<p>Similarly, girls who have a genetic condition called <a href="https://www.nichd.nih.gov/health/topics/cah">congenital adrenal hyperplasia</a> are exposed to unusually high levels of male hormones like testosterone while in the womb, which may masculinize their brain and increase the odds of lesbianism. </p>
<p>It’s also possible that hormonal shifts during pregnancy could affect how a fetus’ brain is configured. In rats, <a href="https://doi.org/10.1210/en.2011-0277">manipulation of hormones during pregnancy</a> produces offspring that exhibit homosexual behavior.</p>
<h2>Why does homosexual behavior exist?</h2>
<p>Several hypotheses have been advanced to explain how homosexuality can be beneficial in perpetuating familial genes. One idea involves the concept of kin selection, whereby people work to ensure the passage of their family’s genes into subsequent generations. Gay uncles and aunts, for example, are “<a href="https://doi.org/10.1177/0956797609359623">helpers in the nest</a>” that help raise other family members’ children to nurture the family tree.</p>
<p>Another idea suggests that homosexuality is a “trade-off trait.” For example, certain genes in women help increase their fertility, but <a href="https://doi.org/10.1111/j.1743-6109.2008.00944.x">if these genes are expressed in a male</a>, they predispose him toward homosexuality.</p>
<p>Sexual behavior is widely diverse and governed by sophisticated mechanisms throughout the animal kingdom. As with other complex behaviors, it is not possible to predict sexuality by gazing into a DNA sequence as if it were a crystal ball. Such behaviors emerge from constellations of hundreds, perhaps thousands, of genes, and how they are regulated by the environment.</p>
<p>While there is no single “gay gene,” there is overwhelming evidence of a biological basis for sexual orientation that is programmed into the brain before birth based on a mix of genetics and prenatal conditions, none of which the fetus chooses.</p>
<p>[ <em>You’re smart and curious about the world. So are The Conversation’s authors and editors.</em> <a href="https://theconversation.com/us/newsletters?utm_source=TCUS&amp;utm_medium=inline-link&amp;utm_campaign=newsletter-text&amp;utm_content=youresmart">You can read us daily by subscribing to our newsletter</a>. ]</p><img src="https://counter.theconversation.com/content/122764/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Bill Sullivan does not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>A new study of nearly 500,000 individuals finds that many genes affect same-sex behavior, including newly identified candidates that may regulate smell and sex hormones.Bill Sullivan, Professor of Pharmacology & Toxicology, Indiana UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1164482019-05-09T20:07:52Z2019-05-09T20:07:52ZTen ethical flaws in the Caster Semenya decision on intersex in sport<figure><img src="https://images.theconversation.com/files/273417/original/file-20190508-183103-1eva5jd.jpg?ixlib=rb-1.1.0&amp;q=45&amp;auto=format&amp;w=496&amp;fit=clip" /><figcaption><span class="caption">Caster Semenya is legally female, was from birth raised as female and identifies as a female.</span> <span class="attribution"><a class="source" href="https://www.flickr.com/photos/ciamabue/7968832970/in/photolist-d9bmpU-6WYxJP-gbWqNq-faB1Ei-d2L35o-QYHomP-aciLfF-X6bjAG-27BHwNd-doMJTN-cT2bCb-RNztaz-cTaov7-74mBHV-cUT2rq-dXYK7q-cRCJDY-cQ9hZQ-RoFRBk-24xxRw2-8RuT7h-cUSVzh-dyUu74-dyUuRP-o4j6Zs-d6XYyN-74qwom-cUT6A5-d6XYpL-dyZXuN-6Rdv6M-d6XYw5-a9coyA-6YGtw4-dyZZsS-dyUuyt-d6XYdN-dyUuKK-25Xb6zb-dyZXsq-dyUuWM-25Xb5Zd-dyZXKL-dyZY9s-dyZXvw-dyZYfL-dyZXES-dyUtKa-dyZXq7-dyZXLW">Jon Connell on flickr </a>, <a class="license" href="http://creativecommons.org/licenses/by-nc/4.0/">CC BY-NC</a></span></figcaption></figure><p><em>This essay is part of our occasional series <a href="https://theconversation.com/au/topics/zoom-out-51632">Zoom Out</a>, where authors explore key ideas in science and technology in the broader context of society and humanity.</em></p>
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<p>Middle-distance runner Caster Semenya will need to take hormone-lowering agents, or have surgery, if she wishes to continue her career in her chosen athletic events.</p>
<p>The Court of Arbitration in Sport (<a href="https://www.tas-cas.org/en/index.html">CAS</a>) <a href="https://www.tas-cas.org/en/general-information/news-detail/article/semenya-asa-and-iaaf-executive-summary.html">decided last week</a> to uphold a rule requiring athletes with certain forms of what they call “disorders of sex development” (DSD) – more commonly called “intersex” conditions – to lower their testosterone levels in order to still be eligible to compete as women in certain elite races. </p>
<p>The case was brought to CAS by Semenya, as <a href="https://theconversation.com/caster-semenyas-impossible-situation-testosterone-gets-special-scrutiny-but-doesnt-necessarily-make-her-faster-116407">she argued discrimination</a> linked to a 2018 decision preventing some women, including herself, from competing in some female events. </p>
<p>This ruling is flawed. On the basis of <a href="https://www.ncbi.nlm.nih.gov/pubmed/20702382">science and ethical reasoning</a>, there are ten reasons CAS’s decision does not stand up. </p>
<p>But first let’s take a quick look at the biology involved.</p>
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Read more:
<a href="http://theconversation.com/caster-semenya-how-much-testosterone-is-too-much-for-a-female-athlete-116391">Caster Semenya: how much testosterone is too much for a female athlete?</a>
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<p><a href="https://www.bbc.co.uk/sport/athletics/48128682">Semenya underwent medical testing in 2009</a>: at the time she was told it was a doping test. The results are confidential, but it has been widely reported that she does have an intersex condition. It seems reasonable to assume she has XY chromosomes, as she is covered by the CAS ruling. Her testosterone levels have not been disclosed, but since the ruling applies to her, they must almost certainly be in what they classify as the “male range”.</p>
<p>According to CAS, the DSD regulations require athletes who want to compete in some female events, who have XY chromosomes and in whom testosterone has a biological effect to reduce their natural testosterone levels to an agreed concentration (below 5 nmol/L). </p>
<p>In women referred to as “46 XY DSD” – the most common intersex condition among female athletes – the presence of a Y chromosome causes the development of testes. These do not descend from the abdomen but do produce testosterone. However the receptors for testosterone are abnormal, with the result that the individual develops as female with a vagina, but no ovaries or uterus. Circulating testosterone may have no biological effect in the case of complete androgen insensitivity syndrome (AIS), or some effect in partial AIS.</p>
<p>Now let’s consider what’s wrong with the ruling. </p>
<h2>1. It confuses sex with gender</h2>
<p>Sex refers to biology, and gender refers to social role or self-identification. In sport, the definition of male and female used to be based solely on sex. <a href="https://bjsm.bmj.com/content/39/10/695.info">This was assessed anatomically in the 1960s</a>, then by biological tests such as the presence of a structure called a “Barr body” in cells (found only in genetic females), or the gene for testicular development. </p>
<p>Sex determination was abandoned in the 1990s in favour of gender. From the 2000 Sydney Olympics forwards, <a href="https://bjsm.bmj.com/content/39/10/695.info">there were no tests of gender other than self-identification</a>. </p>
<p>Caster Semenya’s gender is uncontroversially female. She is legally female, was from birth raised as female and identifies as a female. So, on the current definition, Semenya is a female. Indeed, there has been no question of her gender.</p>
<p>Sex determination itself is not simple, with chromosomal, gonadal (presence of ovaries or testes), or secondary sex characteristics (physical) all possible definitions that would include or exclude different groups. </p>
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Read more:
<a href="http://theconversation.com/what-makes-you-a-man-or-a-woman-geneticist-jenny-graves-explains-102983">What makes you a man or a woman? Geneticist Jenny Graves explains</a>
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<p>The CAS decision relates to “XY females with disorders of sexual development.” XY denotes the male sex chromosomes. This reverts back to the old biological categories. Behind this ruling is the view that Semenya is really a man competing in the women’s category. This view is embodied beautifully in an article entitled “<a href="https://quillette.com/2019/05/03/a-victory-for-female-athletes-everywhere/">A victory for female athletes everywhere</a>.” </p>
<p>But Semenya is a female by the rules used by the International Association of Athletics Federations (<a href="https://www.iaaf.org/home">IAAF</a>) – so she should be allowed to compete to the best of her potential in her category.</p>
<p>An alternative is to retreat to the old sex-based definition based on the presence of a Y chromosome. But that carries its own questions on definitions, and also comes at great political and individual cost. It would imply that Semenya is a male with a disorder of sexual development. </p>
<h2>2. It discriminates against some forms of hyperandrogenism</h2>
<p>Hyperandrogenism is a term used to describe high levels of testosterone. </p>
<p>But the CAS decision does not cover all forms of hyperandrogenism. It only refers to women who have XY chromosomes, such as <a href="https://www.nhs.uk/conditions/androgen-insensitivity-syndrome/">partial androgen insensitivity syndrome (AIS)</a>. </p>
<p>It does not cover a condition called <a href="https://rarediseases.info.nih.gov/diseases/1467/congenital-adrenal-hyperplasia">congenital adrenal hyperplasia</a>, which can cause elevated levels of testosterone in women with XX chromosomes. </p>
<p>The implication is that XX females are real women, while those with XY chromosomes are not. </p>
<h2>3. It’s based on inadequate science</h2>
<p>The significant problem in partial AIS is that although testosterone is elevated in the blood, the receptors for testosterone do not respond to the hormone in the usual way. That is why these individuals have typical external female physical characteristics. </p>
<p>While the testosterone may have some impact on how the body works, it is impossible to quantify how much effect it is having. For example, the difference testosterone makes between males and females in all events is estimated to be <a href="https://sportsscientists.com/2019/05/on-dsds-the-theory-of-testosterone-performance-the-cas-ruling-on-caster-semenya/">up to 12% (all other items being equal)</a>. But Semenya’s best time is only <a href="https://shows.pippa.io/the-science-of-sport-podcast/episodes/the-caster-semenya-decision-explained">2% faster than her competitors</a>. It is not possible to determine how much of this 2% is due to testosterone, and how much due to other factors about her as an athlete, or her psychology.</p>
<p>The study on which the current decision is based contains only correlations and is flawed in several ways, with a call for its <a href="https://doi.org/10.1007/s40318-019-00143-w">retraction on scientific grounds</a>. It is a single study, conducted by the IAAF and the full data have not been released for independent replication. The sole ground for the claim that Semenya derives “material androgenizing effect” (that is, biological impact) appears to be the “statistical over-representation of female athletes with 46 XY DSD” in the relevant events, as documented in this single, poorly conducted study.</p>
<p>Even if Semenya’s times were to drop after the reduction of testosterone, this could be a side-effect of the drugs used to reduce testosterone, or a function of reductions in mental or physical functions which are themselves legitimate entitlements of the athlete. </p>
<p>Her body has grown up in the presence of a certain level of testosterone of uncertain function. Our bodies are complex, and still poorly understood. A change of this kind may lead to unexpected results. Some of these reductions in functions may be unjust. </p>
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Read more:
<a href="http://theconversation.com/testosterone-why-defining-a-normal-level-is-hard-to-do-113587">Testosterone: why defining a 'normal' level is hard to do</a>
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<p>No one has given a complete description of the role of testosterone in someone like Semenya, nor how much it ought to be reduced to achieve a supposedly fair outcome. The comparisons are only with XX chromosome women, who have a very different physiology and normal functioning testosterone receptors. </p>
<p>Put simply, a level of 5 nMol/L testosterone is meaningless in Semenya’s case because the receptors are not responding in the usual way. It does not achieve a “<a href="https://www.ncbi.nlm.nih.gov/pubmed/20702382">level hormonal playing field</a>”. </p>
<p>This is an example of “decimal point science smokescreen.” There is the impression of much greater confidence and sensitivity than the science warrants by appealing to figures with multiple decimal points. The science around testosterone in intersex conditions is poorly understood, let alone as it applies to individuals. This is a level chosen for convenience, not a level that will negate any perceived advantage, but go no further.</p>
<h2>4. It’s inconsistent with values of sport and human rights</h2>
<p>The self-professed values of sport include the <a href="https://www.wada-ama.org/sites/default/files/resources/files/wada_ethicspanel_setofnorms_oct2017_en.pdf">development of one’s own talent</a> . </p>
<p>Yet Semenya is asked to cobble her natural potential as a female competitor. She must take risky biological interventions to reduce her performance. </p>
<p>The United Nations Human Rights Council has stated that the regulations <a href="https://theconversation.com/its-not-clear-where-human-rights-fit-in-the-legal-ruling-on-athlete-caster-semenya-116417">contravene human rights</a> “including the right to equality and non-discrimination […] and full respect for the dignity, bodily integrity and bodily autonomy of the person”. </p>
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Read more:
<a href="http://theconversation.com/its-not-clear-where-human-rights-fit-in-the-legal-ruling-on-athlete-caster-semenya-116417">It's not clear where human rights fit in the legal ruling on athlete Caster Semenya</a>
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<h2>5. It’s inconsistent with treatment of other athletes</h2>
<p>Other women with disorders resulting in higher than expected levels of testosterone, such as congenital adrenal hyperplasia, are not required to reduce their biological advantage.</p>
<p>Competitors with genetic mutations causing increases in red blood cell mass, and who experience enhanced oxygen-carrying capacity as a result, are not required to reduce their biological levels. </p>
<p>The Finnish skier Eero Mäntyranta had a genetic mutation that boosted his red blood cell count by 25-50% (he produced more blood hormone erythropoetin, or EPO). He and won several Olympic medals with this <a href="https://bjsm.bmj.com/content/bjsports/37/3/192.full.pdf">natural form of doping</a>. </p>
<h2>6. It’s unjust</h2>
<p>The decision is unjust in several ways. </p>
<p>Firstly, it was the IAAF which moved from sex to gender definition of female in 1990s. Semenya has entered competition, trained and competed fairly under the rules. To change them now will be undermine her capacity to compete, work and live, after a lifetime of investment. </p>
<p>If the rules are to be changed, they should not affect athletes who agreed to the current rules, but future athletes. There should be a “grandmother clause” for current athletes, like Semenya or else they are unfairly burdened by the bungles of the IAAF. Even if these rules could be considered justified, they should apply to future athletes as soon as possible after puberty.</p>
<p>Secondly, justice is about giving priority to the worst off in our society – but this ruling adds disadvantage to the worst off. Those with intersex conditions are already stigmatised, discriminated against, in many cases cannot bear children even if they want to. They are the socially disadvantaged. This ruling adds further discrimination and disadvantage.</p>
<p>Thirdly, it sets back integration of intersex people, by stigmatising and marginalising them. We have told them: be yourself, society will accept you. But this sends the message: you are really male, we don’t accept you, you should be castrated.</p>
<h2>7. It is an inappropriate reaction to fear of a ‘slippery slope’</h2>
<p>At the heart of this decision is the fear of displacement of cisgender women on the podia by increasing debate over transgender athletes. <a href="https://quillette.com/2019/05/03/a-victory-for-female-athletes-everywhere/">The concern is</a> that if “XY females” are allowed to compete in the female category, formerly male transgender females will follow and rob cisgender women of their medals. </p>
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Read more:
<a href="http://theconversation.com/explainer-what-does-it-mean-to-be-cisgender-103159">Explainer: what does it mean to be 'cisgender'?</a>
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<p>This is a separate issue. Transgender athletes have normal testosterone receptors and would have grown up in the presence of male levels of testosterone acting on normal receptors. Intersex athletes have not grown up in this way and are typically raised as female.</p>
<p>The perceived problem of transgender domination of female sports can be dealt with by separate rules that do not disadvantage existing intersex athletes, though they will raise contentious issues of their own. </p>
<h2>8. It is disproportionate and unreasonable</h2>
<p>All methods of reducing testosterone involve some risk. For example, the administration of <a href="https://www.ncbi.nlm.nih.gov/pubmed/2960241">high-dose birth control medication</a> involves risk of clots, including fatal lung clots. </p>
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Read more:
<a href="http://theconversation.com/how-to-choose-the-right-contraceptive-pill-for-you-87614">How to choose the right contraceptive pill for you</a>
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<p>These interventions interfere with a normally functioning organism for highly uncertain benefits to other people. This is disproportionate and unreasonable.</p>
<h2>9. It can’t be implemented</h2>
<p>The World Medical Association has advised doctors <a href="https://www.wma.net/news-post/wma-reiterates-advice-to-physicians-not-to-implement-iaaf-rules-on-classifying-women-athletes/">not to administer</a> testosterone-lowering interventions, describing the regulation as “<a href="https://www.wma.net/news-post/wma-urges-physicians-not-to-implement-iaaf-rules-on-classifying-women-athletes/">contrary to international medical ethics and human rights standards</a>”. </p>
<p>Their use would be “off label” and is for purposes other than the athlete’s health. The rules involve “strict liability” which means the athlete is responsible for any failure to comply, even if unintentional and outside of the athlete’s control.</p>
<h2>10. There are fairer, safer alternatives</h2>
<p>I have argued athletes <a href="https://www.bmj.com/content/347/bmj.f6150">should be able take performance-enhancing substances</a> within the normal physiological range. This would mean cisgender female athletes could take testosterone up to 5 nMol/L. This would reduce any advantage Semenya may have.</p>
<p>It would also deal with the problem that <a href="https://link.springer.com/article/10.1007/s40279-014-0247-x">up to 40%</a> of elite athletes are currently doping anyway. Semenya received the <a href="https://www.olympic.org/london-2012/athletics/800m-women">London 2012 800m gold medal</a> after the <a href="https://www.reuters.com/article/us-doping-russia-savinova/savinova-stripped-of-london-games-800m-gold-for-doping-idUSKBN15P1EO">original winner was disqualified for doping</a>. It is highly likely that some of her current competitors are also doping.</p>
<p>No doubt part of the resistance to allowing Semenya to “naturally dope” is that it will encourage other athletes to engage in doping. But they already are, and a better approach to “de-enhancing” Semenya is to <a href="https://www.bmj.com/content/347/bmj.f6150">regulate and monitor the enhancement of other athletes</a>. </p>
<h2>Spectacular fail</h2>
<p>Rarely does a public policy fail so spectacularly on so many ethical grounds. </p>
<p><a href="https://www.tas-cas.org/fileadmin/user_upload/Media_Release_Semenya_ASA_IAAF_decision.pdf">CAS acknowledged</a> that its decision constituted discrimination: </p>
<p>“The panel found that the DSD Regulations are discriminatory but the majority of the panel found that, on the basis of the evidence submitted by the parties, such discrimination is a necessary, reasonable and proportionate means of achieving the IAAF’s aim of preserving the integrity of female athletics in the restricted events.”</p>
<p>The UNHRC <a href="https://documents-dds-ny.un.org/doc/UNDOC/LTD/G19/072/46/PDF/G1907246.pdf?OpenElement">has refuted this claim of proportionality</a>: “there is no clear relationship of proportionality between the aim of the regulations and the proposed measures and their impact”.</p>
<p>This ruling is neither necessary, reasonable nor proportionate. It is simply unjust discrimination.</p>
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Read more:
<a href="http://theconversation.com/caster-semenyas-impossible-situation-testosterone-gets-special-scrutiny-but-doesnt-necessarily-make-her-faster-116407">Caster Semenya's impossible situation: Testosterone gets special scrutiny but doesn't necessarily make her faster</a>
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<p><em>Thanks to Michelle Telfer and Ken Pang for comments</em></p>
<p><em>This article builds on arguments presented in the paper <a href="https://www.ncbi.nlm.nih.gov/pubmed/20702382">Time to re-evaluate gender segregation in athletics?</a>.</em></p><img src="https://counter.theconversation.com/content/116448/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Julian Savulescu receives funding from Uehiro Foundation on Ethics and Education and the Wellcome Trust. </span></em></p>Athlete Caster Semenya will need to take hormone-lowering agents, or have surgery, if she wishes to continue her career in her chosen events. But the decision to ban her is flawed on many grounds.Julian Savulescu, Visiting Professor in Biomedical Ethics, Murdoch Children's Research Institute; Distinguished Visiting Professor in Law, University of Melbourne; Uehiro Chair in Practical Ethics, University of OxfordLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1164072019-05-06T10:37:45Z2019-05-06T10:37:45ZCaster Semenya's impossible situation: Testosterone gets special scrutiny but doesn't necessarily make her faster<figure><img src="https://images.theconversation.com/files/272560/original/file-20190503-103063-57i6mw.jpg?ixlib=rb-1.1.0&amp;q=45&amp;auto=format&amp;w=496&amp;fit=clip" /><figcaption><span class="caption">An arbitration court ruled that the 28-year-old runner must lower her testosterone levels in order to compete.</span> <span class="attribution"><a class="source" href="http://www.apimages.com/metadata/Index/Czech-Republic-Athletics-Continental-Cup/a76d9a3a2be74b81bb27078e493a789a/27/0">AP Photo/Petr David Josek</a></span></figcaption></figure><p>A yearslong saga between a middle-distance runner and her sport’s ruling body may be nearing something that resembles a conclusion.</p>
<p>In 2018, the International Association of Athletics Federations <a href="https://www.iaaf.org/news/press-release/eligibility-regulations-for-female-classifica">dictated</a> that female runners with naturally occurring high testosterone levels and specific “<a href="https://www.ncbi.nlm.nih.gov/pubmed/24337131">differences of sex development</a>” must lower their testosterone in order to compete in events ranging from 400 meters to one mile.</p>
<p>Two-time Olympic champion Caster Semenya challenged the 2018 policy. It was discriminatory, <a href="https://www.tas-cas.org/en/general-information/news-detail/article/semenya-asa-and-iaaf-executive-summary.html">she argued</a>, lacked scientific grounding and did “irreparable harm to affected female athletes.”</p>
<p>But on May 1, in a blow to Semenya and an untold number of other women, the Court of Arbitration for Sport upheld the regulations. The policy is now set to go into effect <a href="https://www.iaaf.org/news/press-release/cas-female-eligibility-regulations">on May 8</a> </p>
<p>As a scholar who studies <a href="https://global.oup.com/academic/product/womens-sports-9780190657703?cc=us&amp;lang=en&amp;">women’s sports</a> I’ve been following this story closely. At the heart of the conflict is how to define “femaleness” for the purpose of athletic competitions. Since sports are segregated by sex, what criteria – if any – should we use to distinguish female from male? </p>
<h2>How we got here</h2>
<p>Monitoring testosterone is the latest version of “sex testing” in women’s sport, <a href="https://www.press.uillinois.edu/books/catalog/85fcr3nh9780252040221.html">a practice that began in the 1930s</a>. </p>
<p>Originally, athletes presented affidavits from their personal and team physicians confirming that they were, in fact, women. In the 1960s, athletic administrators turned to gynecological examinations, visual inspections and chromosomal analyses. In the 1990s, they implemented genetic testing.</p>
<p>By the 21st century, most systematic testing had been discontinued, <a href="https://www.doi.org/10.1080/00336297.2011.10483678">unless someone “challenged” a female athlete’s sex</a>. This happened to Semenya at the <a href="https://www.theguardian.com/sport/2009/aug/19/caster-semenya-800m-world-athletics-championships-gender">2009 Track and Field World Championships</a>. Someone apparently issued such a challenge and the press caught wind of it. The International Association of Athletics Federations confirmed that she was undergoing “gender verification” procedures, just before she cruised to victory in the 800-meter race. </p>
<p>Although her test results were never made public, the IAAF <a href="https://www.press.uillinois.edu/books/catalog/58ctr3rx9780252038167.html">subsequently issued a new policy</a> for women with hyperandrogenism, or high testosterone. Arguing that high testosterone gave these athletes an unfair advantage, hyperandrogenic female athletes had two choices: suppress their testosterone or drop out of the sport.</p>
<p>Indian sprinter <a href="https://www.iaaf.org/athletes/india/dutee-chand-275950">Dutee Chand</a> refused to do either. In 2014, the Sports Authority of India diagnosed her as hyperandrogenic and disqualified her from competition. Chand challenged that disqualification in the Court of Arbitration for Sport, <a href="https://www.tas-cas.org/fileadmin/user_upload/award_internet.pdf">where adjudicators ruled</a> the IAAF had “insufficient evidence” to enforce its policy. The decision gave the organization two years to find evidence that associated enhanced performance with naturally high levels of testosterone. If not, the policy would be invalidated.</p>
<p>As the 2017 deadline approached, researchers affiliated with the IAAF <a href="https://bjsm.bmj.com/content/51/17/1309">published a study</a> that claimed women with high testosterone performed as much as 3% better than those with lower testosterone in a handful of events. </p>
<p>Undeterred by <a href="https://doi.org/10.1007/s40318-019-00143-w">those who exposed the study’s methodological flaws</a>, <a href="https://theconversation.com/a-sexist-policy-may-end-the-career-of-one-of-the-commonwealths-greatest-female-runners-94390">the organization plowed ahead with its regulations</a>, prompting Semenya’s challenge. </p>
<h2>‘Necessary’ discrimination?</h2>
<p>Although it rejected Semenya’s claims, the Court of Arbitration for Sport’s panel <a href="https://www.tas-cas.org/en/general-information/news-detail/article/semenya-asa-and-iaaf-executive-summary.html">conceded</a> that the regulations are “discriminatory” but “necessary” to preserve “the integrity of female athletics.” The regulations are additionally discriminatory, panel members noted, because they “do not impose any equivalent restrictions on male athletes.” </p>
<p>This is something that critics of the policy <a href="https://www.theguardian.com/commentisfree/2018/apr/26/testosterone-ruling-women-athletes-caster-semanya-global-south">have charged from the beginning</a>.</p>
<p>No one is concerned about male athletes with unusually high, naturally occurring testosterone. Taking hormones out of the equation, there are a host of biological advantages that some athletes enjoy over others. Nordic skier Eero Mäntyranta, for example, had a <a href="https://www.penguinrandomhouse.com/books/309105/the-sports-gene-by-david-epstein/9781617230127/">genetic condition</a> that caused the excessive production of red blood cells, giving him an advantage in endurance events. Michael Phelps’ <a href="https://www.businessinsider.com/michael-phelps-rio-olympics-body-swimming-2016-8">unique and optimally shaped swimming body</a> allows him to cut through the water with remarkable speed and efficiency. No one suggests these men should muzzle their assets. </p>
<p>This is because we don’t divide sport into categories based on hemoglobin or foot size, regardless of the advantages each confers. </p>
<p>We do, however, carve sport into male and female categories, and for good reason. <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3761733/">Studies show</a> that elite male athletes tend to outperform elite female athletes by about 10%. Segregating men and women in most elite sports gives women more opportunities to compete and succeed.</p>
<p>Here’s where it gets tricky. If we insist on sexual segregation in sport, how do we decide who’s a female and who’s a male? Do those criteria influence sport performance? And what happens when athletes do not fit neatly into sport’s definition of femaleness?</p>
<p>This is precisely what the new regulations attempt to address, albeit in a clumsy and confounding way. Specifically, the policy is aimed at women who are legally recognized as women but who are diagnosed with specific differences of sex disorders and have high levels of functional testosterone. The IAAF explains that these disorders involve male-typical sex chromosomes and the presence of testes or testicular development. The threshold for women’s testosterone is below the “normal” male range but more than two times higher than the upper limit of the “normal” female range.</p>
<p>Semenya and her supporters argue that since the women affected by the policy are, in fact, women, they should be allowed to compete without restriction. </p>
<p>“I just want to run naturally, the way I was born,” <a href="https://www.telegraph.co.uk/athletics/2018/06/18/caster-semenya-files-legal-case-against-new-testosterone-rule/">she said</a>. “It is not fair that I am told I must change.”</p>
<p>It’s worth noting that although Semenya is the top athlete in her class, her times don’t come anywhere near the times of elite male runners – despite allegedly having “male levels” of testosterone.</p>
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<a href="https://images.theconversation.com/files/272571/original/file-20190503-103057-7epr2a.jpg?ixlib=rb-1.1.0&amp;q=45&amp;auto=format&amp;w=1000&amp;fit=clip"><img alt="" src="https://images.theconversation.com/files/272571/original/file-20190503-103057-7epr2a.jpg?ixlib=rb-1.1.0&amp;q=45&amp;auto=format&amp;w=754&amp;fit=clip" srcset="https://images.theconversation.com/files/272571/original/file-20190503-103057-7epr2a.jpg?ixlib=rb-1.1.0&amp;q=45&amp;auto=format&amp;w=600&amp;h=400&amp;fit=crop&amp;dpr=1 600w, https://images.theconversation.com/files/272571/original/file-20190503-103057-7epr2a.jpg?ixlib=rb-1.1.0&amp;q=30&amp;auto=format&amp;w=600&amp;h=400&amp;fit=crop&amp;dpr=2 1200w, https://images.theconversation.com/files/272571/original/file-20190503-103057-7epr2a.jpg?ixlib=rb-1.1.0&amp;q=15&amp;auto=format&amp;w=600&amp;h=400&amp;fit=crop&amp;dpr=3 1800w, https://images.theconversation.com/files/272571/original/file-20190503-103057-7epr2a.jpg?ixlib=rb-1.1.0&amp;q=45&amp;auto=format&amp;w=754&amp;h=503&amp;fit=crop&amp;dpr=1 754w, https://images.theconversation.com/files/272571/original/file-20190503-103057-7epr2a.jpg?ixlib=rb-1.1.0&amp;q=30&amp;auto=format&amp;w=754&amp;h=503&amp;fit=crop&amp;dpr=2 1508w, https://images.theconversation.com/files/272571/original/file-20190503-103057-7epr2a.jpg?ixlib=rb-1.1.0&amp;q=15&amp;auto=format&amp;w=754&amp;h=503&amp;fit=crop&amp;dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
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<span class="caption">Semenya blows away her female competitors, but her times wouldn’t allow her to compete against the top male runners.</span>
<span class="attribution"><a class="source" href="http://www.apimages.com/metadata/Index/Monaco-Athletics-Diamond-League/174e6fadd6e74e6e94dc77fd571091e1/32/0">AP Photo/Claude Paris</a></span>
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<h2>Sporting rights versus human rights</h2>
<p>The controversy has divided activists for sporting rights and human rights. </p>
<p>The IAAF <a href="https://www.tas-cas.org/en/general-information/news-detail/article/semenya-asa-and-iaaf-executive-summary.html">regards women’s sport</a> as a “protected class” and insists that it must “place conditions” on the female category in order “to ensure fair and meaningful competition.”</p>
<p>Human rights activists disagree. If an athlete is legally a woman, that should be good enough. In fact, the United Nations Human Rights Council <a href="https://ilga.org/downloads/Elimination_of_discrimination_against_women_and_girls_in_sport.pdf">resolved</a> that the new regulations “may not be compatible with international human rights norms and standards.” <a href="https://www.sport24.co.za/OtherSport/Athletics/sas-sports-scientist-tucker-not-enough-evidence-to-curb-caster-20190502">Citing the assertions of esteemed scientists</a> and <a href="https://ewn.co.za/2019/02/21/testosterone-expert-karkazis-says-iaaf-has-no-evidence-to-back-its-claims">bioethicists</a>, the council criticized the “lack of legitimate and justifiable evidence for the regulations.” Put differently, there is no conclusive, incontrovertible correlation between high natural testosterone and better performance. Without such evidence, they argued, the IAAF’s regulations shouldn’t be enforced. </p>
<p>The Court of Arbitration panel members <a href="https://www.tas-cas.org/en/general-information/news-detail/article/semenya-asa-and-iaaf-executive-summary.html">did note</a> that they’re concerned about how the IAAF’s regulations will be practically applied. In addition, the IAAF regards the regulations as a “living document,” which means that it can and probably will change as time goes on. </p>
<p>Will the testosterone restrictions expand to additional track and field events? </p>
<p>Meanwhile, the International Olympic Committee <a href="https://www.cnn.com/2019/05/01/sport/caster-semenya-cas-hearing-spt-intl/index.html">is reportedly working on guidelines</a> to help international federations devise their own policies regarding “gender identity and sex characteristics.” In other words, we can expect to see policies similar to the IAAF’s in other sports.</p>
<p>Semenya has 30 days to appeal the arbitration ruling to the Swiss Federal Tribunal. If this appeal fails, she and countless other women must reduce their testosterone, probably with medication, to keep competing in women’s events. What will this do to their bodies? To the sport? To issues of fairness and human rights? </p>
<p>The Court of Arbitration decision is just one leg in what looks to be a never-ending and perhaps futile relay to establish “fairness” in women’s sports.</p><img src="https://counter.theconversation.com/content/116407/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Jaime Schultz does not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>Sports are segregated by sex. But what happens when athletes don't fit neatly into sport's definition of gender?Jaime Schultz, Associate Professor of Kinesiology, Pennsylvania State UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1164952019-05-03T21:02:27Z2019-05-03T21:02:27ZThe demonization of Caster Semenya continues<figure><img src="https://images.theconversation.com/files/272567/original/file-20190503-103068-1hdwfh2.jpg?ixlib=rb-1.1.0&amp;rect=0%2C270%2C5472%2C3366&amp;q=45&amp;auto=format&amp;w=496&amp;fit=clip" /><figcaption><span class="caption">South Africa&#39;s Caster Semenya in the moments before the women&#39;s 800-meter final during the Diamond League athletics event in Doha, Qatar on May 3. The world champion easily won the race, but her future remains in doubt.</span> <span class="attribution"><span class="source">(AP Photo/Kamran Jebreili)</span></span></figcaption></figure><p>Caster Semenya, one of the world’s greatest female middle-distance runners, may be forced to quit the event she has dominated for a decade. After easily winning the 800-metre race at an international meet in Doha on May 3, the South African athlete was defiant in saying she won’t comply with new restrictions that will be placed on her at future competitions.</p>
<p>“No man, or any other human, can stop me from running,” she said after the race, her first — and possibly last — competition since a controversial ruling by the supreme court of international sport.</p>
<p>Her defiant words were in reaction to <a href="https://www.tas-cas.org/fileadmin/user_upload/Media_Release_Semenya_ASA_IAAF_decision.pdf">a horrible ruling by the Court of Arbitration for Sport</a>, which denied an appeal by Semenya against the policy of track and field’s international governing body.</p>
<p>The International Association of Athletics Federations (IAAF) had previously ruled that female athletes like Semenya who have naturally high levels of testosterone must now take hormone-suppressing drugs to compete in any event between 400 metres and one mile. (There are five such events at the international level.) The court decision means the IAAF rules go into effect May 8.</p>
<p>The IAAF policy is based on bad science, flies in the face of best practice in policy making, overrides human rights and will cause tremendous anxiety and even harm among the female athletes in the world, particularly those in the Global South.</p>
<h2>Rules could cause harm</h2>
<p>Even the Court of Arbitration for Sport cautions that there are serious problems with the IAAF policy, including the potential for harmful side effects that hormonal treatment could cause for the athletes who must now take the medication to compete.</p>
<p>The Canadian Centre for Ethics in Sports, which directs Canada’s anti-doping program, the Canadian Association for the Advancement of Women and Sports and AthletesCAN, the association of Canadian national team athletes, <a href="https://cces.ca/news/cces-caaws-and-athletescan-very-concerned-cas-ruling-iaafs-eligibility-regulations-female">have condemned the decision</a>. Athletics Canada has said <a href="https://athletics.ca/athletics-canada-statement-on-iaaf-female-eligibility-regulations/">it won’t implement the policy in Canada</a>.</p>
<p>Before the judgment was rendered, independent experts for the UN Human Rights group <a href="https://www.ohchr.org/_layouts/15/WopiFrame.aspx?sourcedoc=/Documents/Issues/Health/Letter_IAAF_Sept2018.pdf&amp;action=default&amp;DefaultItemOpen=1">wrote the IAAF urging it to cancel the policy</a>. But some track and field athletes came out to support the policy, insisting that <a href="https://www.insidethegames.biz/articles/1077368/isinbayeva-backs-iaaf-and-says-female-athletes-with-high-testosterone-have-colossal-advantage">female athletes with high levels of testosterone have a “colossal” advantage</a>.</p>
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<img alt="" src="https://images.theconversation.com/files/272569/original/file-20190503-103063-1nba6ah.jpg?ixlib=rb-1.1.0&amp;q=45&amp;auto=format&amp;w=754&amp;fit=clip" srcset="https://images.theconversation.com/files/272569/original/file-20190503-103063-1nba6ah.jpg?ixlib=rb-1.1.0&amp;q=45&amp;auto=format&amp;w=600&amp;h=412&amp;fit=crop&amp;dpr=1 600w, https://images.theconversation.com/files/272569/original/file-20190503-103063-1nba6ah.jpg?ixlib=rb-1.1.0&amp;q=30&amp;auto=format&amp;w=600&amp;h=412&amp;fit=crop&amp;dpr=2 1200w, https://images.theconversation.com/files/272569/original/file-20190503-103063-1nba6ah.jpg?ixlib=rb-1.1.0&amp;q=15&amp;auto=format&amp;w=600&amp;h=412&amp;fit=crop&amp;dpr=3 1800w, https://images.theconversation.com/files/272569/original/file-20190503-103063-1nba6ah.jpg?ixlib=rb-1.1.0&amp;q=45&amp;auto=format&amp;w=754&amp;h=518&amp;fit=crop&amp;dpr=1 754w, https://images.theconversation.com/files/272569/original/file-20190503-103063-1nba6ah.jpg?ixlib=rb-1.1.0&amp;q=30&amp;auto=format&amp;w=754&amp;h=518&amp;fit=crop&amp;dpr=2 1508w, https://images.theconversation.com/files/272569/original/file-20190503-103063-1nba6ah.jpg?ixlib=rb-1.1.0&amp;q=15&amp;auto=format&amp;w=754&amp;h=518&amp;fit=crop&amp;dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
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<span class="caption">Semenya flexes her muscles after winning the gold medal in the women’s 800-metre at the 2016 Summer Olympics in Rio de Janeiro.</span>
<span class="attribution"><span class="source">THE CANADIAN PRESS/Frank Gunn</span></span>
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<p>Why has Semenya been so demonized?</p>
<p>As a professor of kinesiology and physical education who competed in athletics at the 1964 Olympics, it’s my view the explanation is to be found in a misunderstanding of natural testosterone, a narrow misreading of the Olympic values, the distrust engendered by almost century of sex testing in international sports and a failure of leadership on the part of the IAAF.</p>
<p>Synthetic testosterone is justly banned from Canadian and international sports (except for approved therapeutic purposes). If taken carefully, at the time of hard training, it can enable significant strength and speed gains and reduce the risk of injury.</p>
<h2>Not a reliable measure</h2>
<p>But natural testosterone is not the same thing. It may aid performance, but it may not. <a href="https://science.sciencemag.org/content/348/6237/858.full">As Yale University researcher Katrina Karkazis has argued</a>, there is no predictable relationship between natural testosterone and improved performance. Even in the same person, testosterone levels can change over time, depending on a range of factors. It’s not a reliable measure, and it will be very difficult, if not impossible, to monitor without frequent, invasive testing. </p>
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<p>Then there’s the ethical question. On what basis do you exclude athletes because of who they are? Natural testosterone is a human condition. When I used to urge athletes against doping, I often said “play with your own chemicals.” Now the IAAF is banning female athletes who play with their own chemicals. The Court of Arbitration for Sport emphasized that Semenya was not cheating, and that she should be admired for her athleticism and courage.</p>
<p>High natural testosterone occurs from a genetic mutation, not unlike the <a href="https://www.propublica.org/article/muscular-dystrophy-patient-olympic-medalist-same-genetic-mutation">hundreds of other genetic mutations that confer advantage in sports</a>, such as exceptional height, reach and ability to draw oxygen into the blood stream. Virtually every top athlete has at least one of these inherent advantages. The Olympic spirit is to rejoice in the diversity of humankind.</p>
<h2>Fairness? Let’s address these issues</h2>
<p>If the concern is really the fairness of condition, those who fear Semenya should address the huge international differences in personal and national income, the most consistent factor determining athletic performance because of the advantages it can buy in better training facilities, nutrition, coaching, medical assistance and so on.</p>
<p>Why is no effort made to balance out these other factors? Would Canadians who support the IAAF against Semenya like it if they were required to train under the same conditions as their competitors from the Global South? Of course not. </p>
<p>Sadly, Semenya has not been the first highly successful female athlete to be accused of masculine qualities and to face banning from sports. In fact, from the very beginning of high-level women’s sport, <a href="https://slate.com/technology/2019/05/caster-semenya-testosterone-gender-appeal-ruling.html">the best athletes have been so vilified.</a></p>
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<figcaption><span class="caption">Kathrine Switzer, the first woman to compete in the Boston Marathon in 1967, was told women were too delicate to run long distances.</span></figcaption>
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<h2>Sex testing started decades ago</h2>
<p>In the 1930s, the men who controlled sports claimed that such women were “abnormal” and introduced “gender verification” to police them. In the 1960s, when women from the Soviet Union and the newly independent nations of the Global South, many of whom didn’t look like western women, began to win many of the medals, the test was made universal.</p>
<p>Every female athlete I know can recount the stress of “gender verification” and hundreds suffered from the stigma of false positives. <a href="https://www.theglobeandmail.com/sports/gender-testing-at-olympics-abolished-at-last/article25459571/">Worldwide opposition led to the abolition of the universal sex test in 1999</a>, but the very same people who administered it tried again when Semenya raced onto the scene. The legacy of this history continues to pit women against women and poison the sport.</p>
<p>What’s most troubling is the way the IAAF leadership has aggressively campaigned for this test. Instead of standing up for Semenya, admiring her and conducting an educational campaign to clarify the issues, IAAF president Sebastian Coe has made it his personal crusade to chase her from the sport. </p>
<p>But history is on Semenya’s side. As the Court of Arbitration for Sport’s decision acknowledges, there are so many problems with the IAAF policy that no doubt another legal challenge will be mounted before long. </p>
<p>Let’s hope that the next time, gender policing in sports will be abolished once and for all. And let’s hope that more track and field athletes will recognize the justice of Semenya’s cause and support her.</p><img src="https://counter.theconversation.com/content/116495/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Bruce Kidd does not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>The great South African runner Caster Semenya may have competed in her last 800-metre race. She has been demonized for more than a decade, like many other female athletes before her.Bruce Kidd, Professor of Kinesiology, University of TorontoLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1164172019-05-02T22:22:54Z2019-05-02T22:22:54ZIt's not clear where human rights fit in the legal ruling on athlete Caster Semenya<p>On May 1 the Court of Arbitration for Sport (<a href="https://www.tas-cas.org/en/index.html">CAS</a>) issued a highly anticipated ruling involving athlete Caster Semenya and Athletics South Africa as claimants, and the International Association of Athletics Federations (<a href="https://www.iaaf.org/home">IAAF</a>). </p>
<p>The <a href="https://www.tas-cas.org/en/general-information/news-detail/article/semenya-asa-and-iaaf-executive-summary.html">ruling</a> upheld the IAAF’s eligibility regulation that restricted female athletes, including Semenya, with “differences of sex development” – broadly taken to mean high levels of testosterone – from entering certain international athletic events. </p>
<p>It means Semenya <a href="https://theconversation.com/caster-semenya-how-much-testosterone-is-too-much-for-a-female-athlete-116391">will have to take medication</a> to lower her testosterone levels if she wishes to continue competing internationally in running events.</p>
<p>This decision is within the sports law decision-making framework. But what about Semenya’s human rights? <a href="http://ap.ohchr.org/documents/dpage_e.aspx?si=A/HRC/40/L.10/Rev.1">Recent publications</a> from the United Nations Human Rights Council (<a href="https://www.ohchr.org/en/hrbodies/hrc/pages/home.aspx">UNHRC</a>) criticise the “discriminatory regulations” relating to lowering testosterone in female athletes. </p>
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Read more:
<a href="http://theconversation.com/caster-semenya-how-much-testosterone-is-too-much-for-a-female-athlete-116391">Caster Semenya: how much testosterone is too much for a female athlete?</a>
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<p>Semenya’s case shows the challenges in balancing a range of interests in maintaining fair competition. On the one hand, the IAAF’s claim of a “legitimate, necessary and proportionate” method to ensure a level playing field in competitive sport. On the other, the rights of those with hyperandrogenism (a condition where the body produces relatively high levels of testosterone) in competing against females with so-called “normal” testosterone levels.</p>
<h2>Who is Caster Semenya?</h2>
<p>As an athlete competing in IAAF events, 28-year-old Semenya is well known for her athletic prowess in her chosen sport. </p>
<p>The public scrutiny <a href="https://www.theguardian.com/sport/2019/may/01/how-caster-semenya-controversy-unfolded-since-2009-timeline">Semenya endured in 2009</a> when subject to gender testing increased public attention on her physical attributes. </p>
<p>After being cleared to run again, Semenya’s domination continued to raise <a href="https://academic.oup.com/jcem/article/97/11/3902/2836438">controversy</a> about perceived unfairness of being included in female classified events. Others described her physical advantage akin to an adult competing against a child in the <a href="https://www.abc.net.au/news/2018-06-19/caster-semenya-to-challenge-iaaf-female-classification-rule/9884762">same competition</a>.</p>
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Read more:
<a href="http://theconversation.com/testosterone-why-defining-a-normal-level-is-hard-to-do-113587">Testosterone: why defining a 'normal' level is hard to do</a>
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<h2>The IAAF sets the rules</h2>
<p>The IAAF is the legitimate rule-maker in the world of athletics. Athletes agree to be bound by the IAAF rules if they want to compete.</p>
<p>In April 2018 the “Eligibility Regulations for Female Classification (Athletes with Differences of Sex Development)” – known as the <a href="https://www.iaaf.org/news/press-release/eligibility-regulations-for-female-classifica">DSD regulations</a> – were set out. </p>
<p>These established the criteria for women to compete in the female classification of the 400m, 800m and 1500m races and apply to athletes who are <a href="https://academic.oup.com/jcem/article/97/11/3902/2836438">female (or have intersex characteristics)</a> with naturally occurring testosterone levels of above 5 nanomole/L (a measure of concentration) and who experience a “material androgenising effect” (that is, the testosterone has a <a href="https://www.sportsintegrityinitiative.com/caster-semenyas-challenge-to-the-dsd-regulations-its-complicated/">biological effect</a>). </p>
<p>Affected female athletes are required to reduce natural testosterone levels to within the normal female range (i.e. to a level below 5 nanomole/L) by using medication, and maintain that reduced level for at least six months to remain eligible to compete. </p>
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Read more:
<a href="http://theconversation.com/what-makes-you-a-man-or-a-woman-geneticist-jenny-graves-explains-102983">What makes you a man or a woman? Geneticist Jenny Graves explains</a>
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<h2>The role of CAS</h2>
<p>The CAS determines sports-related disputes and bases its rulings on the evidence presented to it and the submissions presented by the parties. The authority of the CAS operates via a series of interlocking arrangements that cascade down through the global governance of sport, and are binding on athletes. </p>
<p>In June 2018, Semenya and Athletics South Africa filed <a href="https://www.lawinsport.com/sports-law-news/item/semenya-asa-and-iaaf-decision?tmpl=component&amp;print=1">arbitration proceedings</a> challenging the validity of the DSD Regulations as <a href="https://www.tas-cas.org/en/general-information/news-detail/article/semenya-asa-and-iaaf-executive-summary.html">“discriminatory, unnecessary, unreliable and disproportionate”</a>. They claimed that the DSD regulations would cause “grave unjustified and irreparable harm” and questioned the scientific soundness, a concern raised by <a href="https://sportsscientists.com/2018/08/letter-to-bjsm-reinforcing-call-for-retraction-of-iaaf-research-on-testosterone-in-women/">others</a>. </p>
<p>The IAAF disagreed and claimed the DSD regulations were necessary to pursue “the legitimate aim of safeguarding fair competition and protecting the ability of female athletes to <a href="https://www.tas-cas.org/en/general-information/news-detail/article/semenya-asa-and-iaaf-executive-summary.html">compete on a level playing field</a>”. It claimed the DSD regulations were based on the “best available science” and did not discriminate. </p>
<p>On May 1 the CAS Panel upheld the validity of the DSD regulations and considered the DSD Regulations as a “necessary, reasonable and proportionate means of achieving the IAAF’s aim of preserving the <a href="https://www.tas-cas.org/en/general-information/news-detail/article/semenya-asa-and-iaaf-executive-summary.html">integrity of female athletics</a>” </p>
<p>Semenya and Athletics South Africa have thirty days to appeal to the Swiss Federal Tribunal. The IAAF issued a <a href="https://www.iaaf.org/news/press-release/cas-female-eligibility-regulations">media release</a> advising the DSD Regulations effective on 8 May 2019, and calling on affected athletes to consult their medical teams and initiate suppressive treatment.</p>
<h2>It’s also about human rights</h2>
<p>So what are the wider implications of the Semenya case? </p>
<p>In March 2019, the IAAF was criticised by the United Nations Human Rights Council (<a href="https://www.ohchr.org/en/hrbodies/hrc/pages/home.aspx">UNHRC</a>) over <a href="http://ap.ohchr.org/documents/dpage_e.aspx?si=A/HRC/40/L.10/Rev.1">concerns that</a> their “discriminatory regulations […] to medically reduce blood testosterone levels contravene international human rights […] including the right to equality and non-discrimination…and full respect for the dignity, bodily integrity and bodily autonomy of the person”.</p>
<p>With specific reference to the IAAF’s DSD Regulations, the UNHRC <a href="http://ap.ohchr.org/documents/dpage_e.aspx?si=A/HRC/40/L.10/Rev.1">called upon states</a> to “ensure that sporting associations […] refrain from developing and enforcing policies […] that force, coerce or otherwise pressure […] athletes into undergoing unnecessary, humiliating and harmful medical procedures”. </p>
<p>The UNHRC also requested the UN High Commissioner to <a href="http://ap.ohchr.org/documents/dpage_e.aspx?si=A/HRC/40/L.10/Rev.1">prepare a report</a> on the intersection of gender discrimination in sports and human rights to present to the Human Rights Council at its forty-fourth session (likely to be <a href="https://www.ohchr.org/EN/HRBodies/HRC/Pages/Sessions.aspx">held June 2020</a>). </p>
<p>Sport is a special domain, but it is not that special to be immune from the law and human rights. Indeed, Sport Australia <a href="https://www.sportaus.gov.au/integrity_in_sport/inclusive_sport">promotes inclusive sport</a> based on the principle that “every Australian […] should be able to participate in sport […] in a welcoming and inclusive way”.</p>
<p>So the questions remain whether states will take heed of the UNHRC call to action, and how to reconcile this with the IAAF’s stand on gender characteristics falling outside the “normal” range.</p><img src="https://counter.theconversation.com/content/116417/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Annette Greenhow does not work for, consult, own shares in or receive funding from any company or organization that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>Sport is a special domain, but it is not immune from the law and human rights. We're yet to see if the United Nations Human Rights Council will take steps following a new ruling on testosterone.Annette Greenhow, Assistant Professor, Faculty of Law, Bond UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1163912019-05-01T17:56:07Z2019-05-01T17:56:07ZCaster Semenya: how much testosterone is too much for a female athlete?<p>The South African athlete, Caster Semenya, has <a href="https://www.bbc.co.uk/sport/athletics/48102479">lost her case</a> against the athletic governing body, IAAF, which means that she will have to take medication to lower her testosterone levels if she wishes to continue competing internationally in running events. </p>
<p>Last year, the IAAF introduced <a href="https://www.iaaf.org/news/press-release/eligibility-regulations-for-female-classifica">new regulation</a> for female athletes with “difference of sexual development” (DSD). Athletes with circulating testosterone of five nanomoles per litre of blood (5nmol/L) or above and who are androgen-sensitive, have to meet certain criteria if they wish to compete internationally. One criterion is that DSD athlete must use medication to reduce their blood testosterone level to below 5nmol/L for a continuous period of at least six months. </p>
<p>Semenya felt that the IAAF was targeting her, specifically. She took her case to the Court of Arbitration for Sport (CAS), but the court rejected the 28-year-old athlete’s challenge against the IAAF’s new rules. Although CAS found the rules to be discriminatory, it also said that they were “necessary, reasonable and proportionate”.</p>
<h2>Difference of sexual development</h2>
<p>So what exactly is DSD and does a serum testosterone level above 5nmol/L really confer an unfair advantage in running events? DSDs are a group of <a href="https://www.nhs.uk/conditions/disorders-sex-development/">rare conditions</a> that are acquired before birth, where the reproductive organs and genitals don’t develop as expected. While the condition can be inherited, it usually occurs at random. </p>
<p>A person with DSD may have a mix of both male and female sexual characteristics. For example, they may be genetically female, but with reproductive organs that are of the opposite sex (or the other way around), a combination of both male and female, or not clearly either.</p>
<p>As the testes are the primary site of testosterone production, if a female is born with these male reproductive organs, their testosterone level will be high, often reaching <a href="https://theconversation.com/testosterone-why-defining-a-normal-level-is-hard-to-do-113587">male levels</a>. </p>
<p>Testosterone is involved in many factors that may confer athletic benefit including increased muscle size and strength, along with the ability for the blood to deliver oxygen to those working muscles. This is why elite male athletes are generally faster and stronger than females – and also why males don’t compete against females in most sports. Semenya has high levels of testosterone so she will undoubtedly have at least some associated metabolic benefits.</p>
<p>How much benefit testosterone gives female athletes is difficult to define as women cannot convert testosterone into its more potent form and do not possess the same numbers of testosterone receptors (to carry out its actions) as men. The IAAF level of 5nmol/L is still high for female levels, which <a href="https://theconversation.com/testosterone-why-defining-a-normal-level-is-hard-to-do-113587">normally range from 0.1 - 1.8nmol/L</a>. Judging the actual benefit of testosterone and where to draw these lines would require a lot more research and investigation.</p>
<h2>Where does it stop?</h2>
<p>However, Semenya hasn’t artificially altered her testosterone levels and while her condition is rare – and gives her a large advantage as a track athlete, they are naturally occurring – so is it not discrimination to make her change her body to compete? Does this take the phrase “all men are equal” to the extreme and try to make everyone the same, even by artificial measures? And where does this stop? Many genetic physical attributes can contribute to athletic performance such as height, muscle composition and aerobic capacity.</p>
<p>Dutee Chand, the female sprinter who was also barred from competing against women in 2014 because her natural levels of testosterone exceeded guidelines for female athletes, publicly expressed her disbelief as to why she was penalised for her natural body when she competes against women who are taller and from wealthier backgrounds, which certainly put them at an advantage.</p>
<p>Cases like Semenya and Chand will always be contentious and generate more questions than solutions, and there will always be disagreement among athletes and fans over the right way to approach this sensitive issue in elite sport.</p><img src="https://counter.theconversation.com/content/116391/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Daniel Kelly does not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>The question of whether heightened testosterone confers an advantage for some female athletes remains contentious.Daniel Kelly, Lecturer in Biochemistry, Sheffield Hallam UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1135872019-04-16T09:29:51Z2019-04-16T09:29:51ZTestosterone: why defining a 'normal' level is hard to do<figure><img src="https://images.theconversation.com/files/267612/original/file-20190404-123413-1emyzsy.jpg?ixlib=rb-1.1.0&amp;q=45&amp;auto=format&amp;w=496&amp;fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><a class="source" href="https://www.shutterstock.com/download/confirm/509354542?size=medium_jpg">Marc Bruxelle/Shutterstock</a></span></figcaption></figure><p>Testosterone is the main sex hormone in men. It’s best known for its role in the development of male sexual characteristics and physical features, but there are also many surprising and lesser known functions of testosterone that make it an important hormone in health and disease. Identifying whether someone has too much or too little testosterone can predict future diseases and even treat them. But knowing what is high, low or normal for an individual isn’t straightforward.</p>
<p>Testosterone plays an important role in how male reproductive tissues – such as the testicles and the prostate – develop, as well as promoting what are known as secondary sexual characteristics, such as increased muscle, bigger bones, deep voice and the growth of body hair – all the things we associate with being male. Females also produce testosterone, although in much lower amounts. It helps with the growth and maintenance of a woman’s reproductive tissue, strengthens bones and can influence mood and behaviour. </p>
<p>As with many hormones, the importance of testosterone becomes even more apparent when we look at people who don’t have enough. </p>
<p>Doctors measure testosterone in nanomoles per litre (nmol/l) and the reported “normal” healthy range in males is anywhere from <a href="https://academic.oup.com/jcem/article/102/4/1161/2884621">9.2 to 31.8 nmol/L</a>. It is about ten times lower in females, with “normal” levels considered to be between <a href="https://www.mayocliniclabs.com/test-catalog/Clinical+and+Interpretive/83686">0.3 and 2.4 nmol/L</a>. Despite these lower levels in women, testosterone circulates in the blood at higher concentrations than oestrogen, the typical female hormone.</p>
<p>But it is difficult to know what is the right level of testosterone, and these ranges are often <a href="https://www.ncbi.nlm.nih.gov/pubmed/17100942?dopt=Abstract&amp;holding=npg">not agreed on</a> by experts from different societies, countries or laboratories. </p>
<p>Nevertheless, low levels of testosterone in men can result in a lack of energy and strength, a reduced sex drive and putting on weight. Many of these symptoms are actually the same in women who also have low testosterone, and now research suggests that low testosterone can be a risk factor for developing heart disease, diabetes and obesity in both men and women.</p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/267618/original/file-20190404-123397-1edkq1s.jpg?ixlib=rb-1.1.0&amp;q=45&amp;auto=format&amp;w=754&amp;fit=clip" srcset="https://images.theconversation.com/files/267618/original/file-20190404-123397-1edkq1s.jpg?ixlib=rb-1.1.0&amp;q=45&amp;auto=format&amp;w=600&amp;h=400&amp;fit=crop&amp;dpr=1 600w, https://images.theconversation.com/files/267618/original/file-20190404-123397-1edkq1s.jpg?ixlib=rb-1.1.0&amp;q=30&amp;auto=format&amp;w=600&amp;h=400&amp;fit=crop&amp;dpr=2 1200w, https://images.theconversation.com/files/267618/original/file-20190404-123397-1edkq1s.jpg?ixlib=rb-1.1.0&amp;q=15&amp;auto=format&amp;w=600&amp;h=400&amp;fit=crop&amp;dpr=3 1800w, https://images.theconversation.com/files/267618/original/file-20190404-123397-1edkq1s.jpg?ixlib=rb-1.1.0&amp;q=45&amp;auto=format&amp;w=754&amp;h=503&amp;fit=crop&amp;dpr=1 754w, https://images.theconversation.com/files/267618/original/file-20190404-123397-1edkq1s.jpg?ixlib=rb-1.1.0&amp;q=30&amp;auto=format&amp;w=754&amp;h=503&amp;fit=crop&amp;dpr=2 1508w, https://images.theconversation.com/files/267618/original/file-20190404-123397-1edkq1s.jpg?ixlib=rb-1.1.0&amp;q=15&amp;auto=format&amp;w=754&amp;h=503&amp;fit=crop&amp;dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Low testosterone can increase the risk of obesity, in men and women.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/download/confirm/1212097219?size=medium_jpg">India Picture/Shutterstock</a></span>
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<h2>The Goldilocks zone</h2>
<p>Really high testosterone levels in men tend not to occur naturally, but it is known that male athletes abusing testosterone or other similar steroids for performance gains often have problems with their heart. Likewise, certain diseases in women that result in high testosterone also lead to similar risks for heart disease. This means that testosterone appears to be best for health when it stays within a certain range: not too high and not too low. </p>
<p>Complicating this matter is the fact that testosterone levels don’t stay the same through life, through the year or even through the day – at least in men. Testosterone levels change throughout the day in men, peaking at around <a href="https://www.sciencedirect.com/science/article/pii/0039128X73901104">4-8am and falling to their lowest at about 12 hours later</a>. They can also vary across the year, although these seasonal highs and lows will differ around <a href="https://www.ncbi.nlm.nih.gov/pubmed/22790643">the world</a>. These daily and seasonal variations can see levels change by as much as 19%.</p>
<p>Men’s testosterone levels in the blood are thought to fall with age, although this may actually be more related to diseases that occur with age. Women’s testosterone levels are a bit more stable, without any known daily or yearly changes. As with men, however, they also decrease a little with age. And it is these falling levels that increase the risk of disease. </p>
<p>Complicating matters even further is the fact that everybody is different, particularly in the way that testosterone works. </p>
<h2>Approximations of the truth</h2>
<p>Testosterone takes action when it joins onto its receptor in any particular cell in our body. But how well it does this to bring about the functions mentioned above differs from person to person, which is influenced by genetics. So what might be considered a low level for one person may actually be OK if they have a more sensitive receptor capable of carrying out testosterone’s actions at lower concentrations. In fact, when we look at some diseases in men that are thought to result from low testosterone, not everyone below the normal range develops the disease.</p>
<p>It is unclear whether it is also due to similar genetic factors, but testosterone can also be different depending on where you <a href="https://www.nature.com/articles/s41559-018-0567-6">live and how wealthy you are</a>. So a universal “normal range” may not apply to all groups of people. </p>
<p>Establishing a “normal” level is complex, and measuring testosterone on its own may not be enough to estimate what is the correct level to have in the blood for any one person. Still, research tries to define levels that are healthy, and levels that may be related to disease so patients can be identified and treated. Still, these are approximations of the truth in specific populations with specific genetics, backgrounds and disease. Like the story of the <a href="https://www.allaboutphilosophy.org/blind-men-and-the-elephant.htm">blind men feeling different parts of an elephant</a>, we can only build up a picture of the truth from small parts in the search to find the answers.</p>
<p>Using average levels of testosterone from lots of people from different populations to establish normal ranges is useful to help identify people outside of this range with a related disease. But many factors have to be considered when deciding whether someone has normal testosterone or not and whether there truly is a “normal” testosterone level at all.</p><img src="https://counter.theconversation.com/content/113587/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Daniel Kelly does not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>So-called normal levels of testosterone are approximations, but can help researchers investigate disease and treatments.Daniel Kelly, Lecturer in Biochemistry, Sheffield Hallam UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1118772019-02-14T21:40:01Z2019-02-14T21:40:01ZMove over testosterone, another hormone is also vital for making boys – and it doesn't come from the testes<figure><img src="https://images.theconversation.com/files/259112/original/file-20190214-1751-1i0273f.jpg?ixlib=rb-1.1.0&amp;q=45&amp;auto=format&amp;w=496&amp;fit=clip" /><figcaption><span class="caption">Little boy blue. </span> <span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/newborn-4-day-old-baby-boy-115541389?src=iUQ6kT-yWLCpx-YHU2uQMg-1-91">noBorders - Brayden Howie</a></span></figcaption></figure><p>Often the first question parents are asked after the birth of their child is “congratulations, girl or boy?”. For <a href="https://www.ncbi.nlm.nih.gov/pubmed/17875484">parents of</a> one in 2,000 to 4,000 births, however, there is not an easy answer. This is when the baby has “ambiguous” genitalia, where it is not clear which sex they belong to. In baby boys, this was long thought to be caused by problems linked to testosterone – as were more common disorders such as undescended testicles and malformed penises, which <a href="https://www.ncbi.nlm.nih.gov/pubmed/20865786">respectively occur</a> in 9% and 1% of births. </p>
<p>But now it is clear that the reality is slightly different. According <a href="http://journals.plos.org/plosbiology/article?id=10.1371/journal.pbio.3000002">to new research</a> in which I am a co-author, another hormone known as androsterone – which originates in the placenta and foetal adrenal gland – is also vital to the process that turns foetuses in boys. These insights have the potential to make a big difference to how we treat sexual disorders in male babies in future – and are also relevant to the whole debate about male and female identity. </p>
<p>Even small children are aware that men and women usually look different. It is common knowledge that boys become men because the testes of the man produce the “male” hormone testosterone and, in turn, testosterone makes men masculine. We know this thanks to the French endocrinologist Alfred Jost’s <a href="https://www.ncbi.nlm.nih.gov/pubmed/18577872">groundbreaking studies</a> in the early 1950s.</p>
<p>There are several times in boys’ lives in which bursts of testosterone play a key role in their development as males. The most well known is of course puberty, in which the testes start making much more testosterone. This makes boys hairier, grows their genitals and makes their voices break. </p>
<p>The other times are the “<a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4462291/">mini-puberty</a>” that takes place at around three months after birth, which leads certain changes in the testes and brain; and when a boy is still a foetus in the womb, around three months into his mother’s pregnancy. While all these bursts of testosterone are probably very important in making a normal male, it is the one in the womb that affects whether the child will be a boy at all. What is now clear is that testosterone and the testes have been hogging the podium when in fact we need to share the honours around. </p>
<h2>Testosterone and super-testosterone</h2>
<p>Testosterone is part a family of male sex hormones called androgens. To get a normal male, testosterone needs to be turned into another androgen called dihyrotestosterone or DHT, a “super-testosterone” that is five times more potent than its cousin. This conversion is done in the tissue of what will become the penis, along with the other parts of the body that develop male characteristics. The consequences of the process are clear: boys who cannot turn testosterone into DHT are born looking female and only become more obviously male at puberty. </p>
<p>These include the <em><a href="https://www.bbc.co.uk/news/magazine-34290981">Guevedoces</a></em> in the Dominican Republic, who, due to a genetic mutation, lack the enzymes to make the DHT conversion. Studying these extraordinary children in the early 1970s led the American researcher <a href="http://vivo.med.cornell.edu/display/cwid-jimperat">Julianne Imperato-McGinley</a> to <a href="http://science.sciencemag.org/content/186/4170/1213">develop</a> the drug finasteride to treat prostate cancer. </p>
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<p>For years, this story was considered complete – masculinisation was due to testosterone and the conversion of testosterone to DHT. Then an Australian zoologist named Marilyn Renfree, in an elegant <a href="https://www.ncbi.nlm.nih.gov/pubmed/12538619">series of studies</a> in the 2000s, <a href="https://www.newscientist.com/article/dn18782-how-female-wallabies-boost-their-males-testosterone/">published</a> the first evidence that things may not be that simple. She was actually studying wallabies, since the young in the pouch were easily accessible for experimental purposes and they mimic much of the period of pregnancy in humans and other <a href="http://www.ucmp.berkeley.edu/mammal/eutheria/placental.html">mammals with placentas</a>. Renfree found that the genitals of the young male wallabies made DHT even without testosterone from their testes. The only reliable conclusion was that they were converting other androgens to DHT.</p>
<p>It became clear that there are two ways to make a “male signal” in a wallaby foetus, both of which are necessary to normal sexual development. The first is by testosterone from the testes. The second is through different androgens that can also be made by other organs in the human, including the foetus’s adrenal glands, liver and the placenta. These other processes came to be known as the “backdoor” pathway. </p>
<p>But was the same thing true in humans? It was <a href="https://www.ncbi.nlm.nih.gov/pubmed/17875484">later shown</a> that it was, by studying male human newborns who were not properly masculinised; they had undescended testes and ambiguous genitals, despite having testes that made testosterone. It turned out they were unable to make the backdoor androgens because they had mutations in the genes of enzymes that were key to the process of the conversion into DHT. </p>
<p>As further evidence that both types of male signal are essential to normal development of human male foetuses, it was <a href="https://www.ncbi.nlm.nih.gov/pubmed/28755466">also discovered</a> that foetuses whose placentas are not working properly are around twice as likely to be born with undescended testes or with malformed penises – especially if they are also born abnormally small (for their gestational age). </p>
<h2>What we have shown</h2>
<p>In our research, which also involved the University of Glasgow and French and Swedish collaborators, we have been able to explain why. We measured the levels of different male sex hormones in the blood of male and female foetuses, and were surprised to find that only two androgens were higher in males than females: testosterone and androsterone. The relevance to the placenta is that it is up to 6,000 times heavier than the foetus and it makes large amounts of a hormone called progesterone, which it can convert into androsterone – as can the foetal liver and adrenal glands. The human foetuses’ testes have no ability to make this conversion. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/259115/original/file-20190214-1758-lk1cj8.jpg?ixlib=rb-1.1.0&amp;q=45&amp;auto=format&amp;w=1000&amp;fit=clip"><img alt="" src="https://images.theconversation.com/files/259115/original/file-20190214-1758-lk1cj8.jpg?ixlib=rb-1.1.0&amp;q=45&amp;auto=format&amp;w=754&amp;fit=clip" srcset="https://images.theconversation.com/files/259115/original/file-20190214-1758-lk1cj8.jpg?ixlib=rb-1.1.0&amp;q=45&amp;auto=format&amp;w=600&amp;h=600&amp;fit=crop&amp;dpr=1 600w, https://images.theconversation.com/files/259115/original/file-20190214-1758-lk1cj8.jpg?ixlib=rb-1.1.0&amp;q=30&amp;auto=format&amp;w=600&amp;h=600&amp;fit=crop&amp;dpr=2 1200w, https://images.theconversation.com/files/259115/original/file-20190214-1758-lk1cj8.jpg?ixlib=rb-1.1.0&amp;q=15&amp;auto=format&amp;w=600&amp;h=600&amp;fit=crop&amp;dpr=3 1800w, https://images.theconversation.com/files/259115/original/file-20190214-1758-lk1cj8.jpg?ixlib=rb-1.1.0&amp;q=45&amp;auto=format&amp;w=754&amp;h=754&amp;fit=crop&amp;dpr=1 754w, https://images.theconversation.com/files/259115/original/file-20190214-1758-lk1cj8.jpg?ixlib=rb-1.1.0&amp;q=30&amp;auto=format&amp;w=754&amp;h=754&amp;fit=crop&amp;dpr=2 1508w, https://images.theconversation.com/files/259115/original/file-20190214-1758-lk1cj8.jpg?ixlib=rb-1.1.0&amp;q=15&amp;auto=format&amp;w=754&amp;h=754&amp;fit=crop&amp;dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
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<span class="caption">Foetal development.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-illustration/3d-rendered-medically-accurate-illustration-fetus-727111831?src=_Sa4j1zE-PH_P17EdzcYww-1-28">Sebastian Kaulitzki</a></span>
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<p>We then also showed that the testosterone and adrosterone were converted into DHT in male target tissues like the penis. And not only are both androgens required to masculinise the foetus, there can be abnormalities where levels are lower than normal: for example, a good index of the degree of masculinisation is the distance between the anus and genitals, and this is shorter than usual in newborns with malformed penises. </p>
<p>People affected by disorders of sexual development, including malformed penises, can have a very difficult time and face delicate surgery, hormone therapy and other treatments. Every new piece of information into how masculinisation happens raises the prospect of improving when and how these disorders are detected and treated in future. Early enough diagnosis of reduced placental function related to androgen production in early pregnancy might enable treatment before penis formation is complete, avoiding the need for corrective surgery later in life. </p>
<p>A final take-home message from our study is that while testosterone and androsterone are indeed higher on average in male than female foetuses, the difference is quite small. There is also considerable overlap between the lowest levels in boys and the highest levels in girls. Those in society who are adamant that the only choice for people is a binary choice of man or woman are not basing their views on biological reality. Treasured beliefs about the supremacy of testosterone and the testes in making a man are also obviously flawed.</p><img src="https://counter.theconversation.com/content/111877/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Paul Fowler receives/has received funding from the MRC, BBSRC, Wellcome Trust, European Commission, Chief Scientist Office, NHS Grampian Endowment, Glasgow Children’s Hospital Charity, Tenovus, Society for the Study of Fertility, Society for Endocrinology, Endocrine Society, Holly Hill Trust, Arthritis Research UK, Royal Society.</span></em></p>What we thought we knew about male development since the 1950s has now been turned on its head.Paul A. Fowler, Chair in Translational Medical Services, University of AberdeenLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1116252019-02-14T19:07:53Z2019-02-14T19:07:53ZYou need more than just testes to make a penis<figure><img src="https://images.theconversation.com/files/258965/original/file-20190214-1721-14ua0u2.jpg?ixlib=rb-1.1.0&amp;q=45&amp;auto=format&amp;w=496&amp;fit=clip" /><figcaption><span class="caption">Testosterone is primarily made in the testes, and creates many of the characteristics we see in adult men. </span> <span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/jeans-man-on-dark-background-766127614">from www.shutterstock.com</a></span></figcaption></figure><p>In prenatal ultrasounds or at delivery, many new parents look between their baby’s legs: the presence of a penis is taken as a strong sign that it’s a boy.</p>
<p>For humans and other animals, development of a penis was thought to be driven by “male hormones” (androgens) produced entirely by the testes of the male fetus as it grows in the uterus. </p>
<p>However, a <a href="http://journals.plos.org/plosbiology/article?id=10.1371/journal.pbio.3000002">new paper</a> released today indicates this might not be the case. Instead, some of the masculinising hormones that drive penis development may come from other sources in the developing fetus. These include the liver, the adrenals (small glands found on the kidneys) and placenta. </p>
<p>For the first time, this work comprehensively looks at the possible sites of hormone production outside the testes and their role in regulating masculinisation – the process of gaining typical male characteristics. This helps us see how we develop as embryos, and might feed into a bigger picture of why disorders of penis development are increasing.</p>
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Read more:
<a href="http://theconversation.com/our-relationship-with-dick-pics-its-complicated-103444">Our relationship with dick pics: it's complicated</a>
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<h2>Testosterone is not enough</h2>
<p>The penis develops from an embryonic structure called the genital tubercle or GT. </p>
<p>The GT is present in both males and females, and develops into either a clitoris or penis, depending on its exposure to hormones secreted by the developing gonads (ovaries or testes). </p>
<p>In females, the developing ovaries do not produce early hormones and the GT becomes feminised, forming a clitoris. </p>
<p>In males, the developing testes produce testosterone. This circulates in the developing fetus and causes masculinisation of target tissues and induces penis development from the GT. </p>
<p>Testosterone itself is a relatively weak hormone. It is converted in the penis to another hormone called dihydrotestosterone (DHT), which has a much more potent masculinising effect. </p>
<p>It is the local conversion of testosterone to DHT within the tissue that is important for penis development and other changes. </p>
<p>There are several ways in which the fetus can make DHT. The most simple is via conversion from testicular testosterone (the so-called “canonical” pathway). However, DHT can also be produced via other steroid hormone pathways active in many tissues, which is explored further in this new paper. </p>
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<p>
<em>
<strong>
Read more:
<a href="http://theconversation.com/what-makes-you-a-man-or-a-woman-geneticist-jenny-graves-explains-102983">What makes you a man or a woman? Geneticist Jenny Graves explains</a>
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<h2>Common birth defects</h2>
<p>Understanding the pathways that control penis development is important. Disorders affecting penis development are among the most common birth defects seen in humans, with hypospadias (a disorder affecting development of the urethra) currently affecting around <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2083775/">1 in every 115 live males born in Australia</a>, and rates are on the rise. </p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/258647/original/file-20190213-90504-lw517s.jpg?ixlib=rb-1.1.0&amp;q=45&amp;auto=format&amp;w=754&amp;fit=clip" srcset="https://images.theconversation.com/files/258647/original/file-20190213-90504-lw517s.jpg?ixlib=rb-1.1.0&amp;q=45&amp;auto=format&amp;w=600&amp;h=424&amp;fit=crop&amp;dpr=1 600w, https://images.theconversation.com/files/258647/original/file-20190213-90504-lw517s.jpg?ixlib=rb-1.1.0&amp;q=30&amp;auto=format&amp;w=600&amp;h=424&amp;fit=crop&amp;dpr=2 1200w, https://images.theconversation.com/files/258647/original/file-20190213-90504-lw517s.jpg?ixlib=rb-1.1.0&amp;q=15&amp;auto=format&amp;w=600&amp;h=424&amp;fit=crop&amp;dpr=3 1800w, https://images.theconversation.com/files/258647/original/file-20190213-90504-lw517s.jpg?ixlib=rb-1.1.0&amp;q=45&amp;auto=format&amp;w=754&amp;h=533&amp;fit=crop&amp;dpr=1 754w, https://images.theconversation.com/files/258647/original/file-20190213-90504-lw517s.jpg?ixlib=rb-1.1.0&amp;q=30&amp;auto=format&amp;w=754&amp;h=533&amp;fit=crop&amp;dpr=2 1508w, https://images.theconversation.com/files/258647/original/file-20190213-90504-lw517s.jpg?ixlib=rb-1.1.0&amp;q=15&amp;auto=format&amp;w=754&amp;h=533&amp;fit=crop&amp;dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">The urethra, the hole through which urine passes out of the body, is found in a range of different locations in the disorder known as hypospadias</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-vector/newborn-malformation-hypospadia-main-types-315283037?src=q7V1zs7wS25RVKHm_q7jsg-1-2">from www.shutterstock.com</a></span>
</figcaption>
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<p>In fact, the incidence of hypospadias has <a href="https://www.ncbi.nlm.nih.gov/pubmed/11392374">doubled over the past 40 years</a>. Such a rapid increase in incidence has been attributed to environmental factors, with endocrine disrupting chemicals (EDCs) being proposed as a major cause. EDCs are man-made chemicals used in many industries – for example, in the production of plastics, cosmetics, flame retardants and pesticides. They can interfere with hormone and metabolic systems in our bodies.</p>
<p>Of the <a href="https://endocrinedisruption.org/interactive-tools/tedx-list-of-potential-endocrine-disruptors/search-the-tedx-list">1,484 EDCs currently identified</a>, a large number are known to negatively affect male reproductive development. </p>
<p>Many <a href="https://www.publish.csiro.au/RD/RD18505">studies</a> have identified how EDCs negatively affect organs, such as the liver and adrenals, leading to diseases and disorders which damage the health of these organs and disturb male development. </p>
<h2>Backdoor pathway</h2>
<p>By measuring hormones from blood samples and tissues during the second trimester of human fetal development, this new research helps us understand the pathways driving the production of DHT, and masculinisation of the penis. </p>
<p>It suggests that in addition to the canonical pathway (testosterone from the testis converted to DHT in the GT and driving penis development), male steroids are synthesised by other organs, such as the placenta, liver and adrenal gland via a process called the “backdoor” pathway to contribute to masculinisation. Notably, the backdoor pathway was <a href="https://www.ncbi.nlm.nih.gov/pubmed/12538619">first discovered</a> through research conducted here in Australia on marsupials. </p>
<p>The findings of this research suggest that EDCs might have effects in non-reproductive tissues, including the adrenals and liver, and then cause male reproductive diseases such as hypospadias. </p>
<p>Also, it indicates that placental defects, such as intrauterine growth restriction that results in babies being born small, might contribute to male reproductive diseases in humans. </p>
<p>Further research is now required to follow-up on these interesting findings to explore possible new causal pathways of disorders that begin during pregnancy.</p><img src="https://counter.theconversation.com/content/111625/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Dr Mark Green receives funding from the National Health and Medical Research Council, as well as the University of Melbourne for his research on fertility and endocrine disruptors. He is the Secretary for the Society for Reproductive Biology (SRB) and advisor on the effects of endocrine disruptors to the Victorian Assisted Reproductive Treatment Authority (VARTA). </span></em></p><p class="fine-print"><em><span>Andrew Pask receives funding from the Australian Research Council and National Health and Medical Research Council. </span></em></p>Disorders affecting penis development are among the most common birth defects seen in humans, and rates are on the rise.Mark Green, Merck Serono Senior Lecturer in Reproductive Biology, University of MelbourneAndrew Pask, Professor, University of MelbourneLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/1054242018-10-23T12:48:17Z2018-10-23T12:48:17ZStudy shows equality frees women to follow traditional gender choices – or does it?<figure><img src="https://images.theconversation.com/files/241837/original/file-20181023-169801-18k952m.jpg?ixlib=rb-1.1.0&amp;q=45&amp;auto=format&amp;w=496&amp;fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/beautiful-african-american-woman-her-daughter-590562002?src=zyFpU8UMQOG2kT0p0un9Rw-1-0">Tijana M/Shutterstock</a></span></figcaption></figure><p>If you want gender equality, get rich. Research shows that men and women tend to be more equal in <a href="http://reports.weforum.org/global-gender-gap-report-2015/the-case-for-gender-equality/">more developed countries</a>. You might expect that the more equal opportunities in these countries might reduce other differences between the genders, such as what kind of jobs people are more likely to have, or personality traits such as kindness or a tendency for risk-taking. But a new study <a href="http://science.sciencemag.org/cgi/doi/10.1126/science.aas9899">published in Science</a> argues the opposite, that greater equality actually widens these kind of gender differences.</p>
<p>Cleverly, the study doesn’t claim that gender preferences are culturally learnt or biologically driven. Instead, it simply describes them as “intrinsic” and says you can be agnostic about their origin. In avoiding the discussion about where these differences come from, the article simply treats gender preferences as a black box that economists and others shouldn’t open.</p>
<p>Yet while the study looked at data from all over the world to build its case, I believe it reaches the wrong conclusions simply by assuming that men and women have different preferences that are free to be expressed in more developed countries. Removing legal barriers to equal opportunity isn’t the same as removing <a href="https://theconversation.com/would-gender-differences-exist-if-we-treated-all-people-the-same-from-birth-68181">the social pressures</a> that help shape traditional beliefs about gender roles.</p>
<p>There are two ideas that could explain whether traditional gender roles and preferences are likely to increase or decrease as a country gets richer. The <a href="https://onlinelibrary.wiley.com/doi/abs/10.1002/9781118663219.wbegss183">social role hypothesis</a> says that gender roles defined by unequal opportunity instil differences in preferences. So when women have the same opportunities as men, these differences should disappear.</p>
<p>On the other hand, the resource hypothesis says that gender preferences <a href="https://pubsonline.informs.org/doi/abs/10.1287/mnsc.2015.2244?journalCode=mnsc">aren’t created by gender roles</a>. And once men and women have similar opportunities they are freer to express their “natural” inner differences.</p>
<h2>What the study shows</h2>
<p>Drawing on data from 80,000 people in 76 countries, the new research provides evidence to support the second hypothesis. In countries where economic growth had helped create more equal opportunities, men were more likely to take risks. Meanwhile, women were more likely to be trusting and kind, and less willing to postpone rewards to get more in the future. Because these results follow greater economic and social freedom, they supposedly show that these gender differences are intrinsic, and explain why men are more focused on their careers and women on their families.</p>
<p>The problem hidden in the logic of the study is that attitudes and preferences are not intrinsic. They are not characteristics we are born with, that we can simply add as a variable in an economic model correlating them with economic growth. We develop attitudes from an early age over the whole course of our lives, learning from <a href="https://eige.europa.eu/gender-mainstreaming/resources/european-union/you-are-who-you-know-network-approach-gender">everyone we interact with</a>. This includes family members, teachers and other role models, as well as other children in our schools and later colleagues in our workplaces.</p>
<p><a href="http://aris.ss.uci.edu/%7Elin/52.pdf">In this way</a>, we learn that women should be caring and men successful, that girls should be altruistic and boys risk-taking. These gender stereotypes are then reinforced throughout our lives because society is structured to make women more likely to look after children and so tend to interact more with teachers and other mums. Men are more likely to spend more time on their careers and their social networks are more varied and offer more opportunities.</p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/241839/original/file-20181023-169807-1w88bez.jpg?ixlib=rb-1.1.0&amp;q=45&amp;auto=format&amp;w=754&amp;fit=clip" srcset="https://images.theconversation.com/files/241839/original/file-20181023-169807-1w88bez.jpg?ixlib=rb-1.1.0&amp;q=45&amp;auto=format&amp;w=600&amp;h=400&amp;fit=crop&amp;dpr=1 600w, https://images.theconversation.com/files/241839/original/file-20181023-169807-1w88bez.jpg?ixlib=rb-1.1.0&amp;q=30&amp;auto=format&amp;w=600&amp;h=400&amp;fit=crop&amp;dpr=2 1200w, https://images.theconversation.com/files/241839/original/file-20181023-169807-1w88bez.jpg?ixlib=rb-1.1.0&amp;q=15&amp;auto=format&amp;w=600&amp;h=400&amp;fit=crop&amp;dpr=3 1800w, https://images.theconversation.com/files/241839/original/file-20181023-169807-1w88bez.jpg?ixlib=rb-1.1.0&amp;q=45&amp;auto=format&amp;w=754&amp;h=503&amp;fit=crop&amp;dpr=1 754w, https://images.theconversation.com/files/241839/original/file-20181023-169807-1w88bez.jpg?ixlib=rb-1.1.0&amp;q=30&amp;auto=format&amp;w=754&amp;h=503&amp;fit=crop&amp;dpr=2 1508w, https://images.theconversation.com/files/241839/original/file-20181023-169807-1w88bez.jpg?ixlib=rb-1.1.0&amp;q=15&amp;auto=format&amp;w=754&amp;h=503&amp;fit=crop&amp;dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
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<span class="caption">Tradition holds men are naturally more aggressive and risk-taking.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/sao-paulo-brazil-june-19-2004-317336375?src=DOGlEvKq57g4gRsVHwN1-w-1-21">Alf Ribeiro/Shutterstock</a></span>
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<p>These differences result in what we call <a href="https://www.sup.org/books/title/?id=1416">horizontal segregation</a>, where women end up in so-called “pink collar” jobs because they are more likely to find out about vacancies from other women. When women do end up in male-dominated jobs, they have to face <a href="https://www.emeraldinsight.com/doi/abs/10.1108/03090590110407191">vertical segregation</a>, making it almost impossible for them to reach leading roles. We see this in the well-documented lack of female leaders <a href="https://www.weforum.org/agenda/2017/11/women-leaders-key-to-workplace-equality/">in many industries</a>.</p>
<p>A counter-argument would be that these gender differences really are intrinsic because they depend on biological factors, such as the different levels of sex hormones men and women tend to have. There is now a solid stream of research that looks at how hormones such as testosterone and oestrogen may explain gender behaviour.</p>
<p>Evidence shows that hormones may well influence <a href="https://www.ncbi.nlm.nih.gov/pubmed/21334362">sexual identity</a>, the likelihood of developing <a href="http://journals.sagepub.com/doi/10.2190/PM.46.2.g">certain diseases</a>, and <a href="https://www.sciencedirect.com/science/article/pii/S0306453012001588">male aggression</a> (although results are controversial). But there is no evidence that this is directly related to gender preferences in risk-taking, patience, trust and reciprocity. Interestingly, <a href="https://www.ncbi.nlm.nih.gov/pubmed/19699203">some studies</a> show that while hormones seem to suggest an influence on male behaviour, the same effect is not found in females.</p>
<p>Studies that have looked at these biological factors also stress that they don’t fully explain gender differences in behaviours and preferences, because these are reinforced <a href="https://link.springer.com/article/10.1007/s11199-012-0120-z">in boys</a> <a href="https://www.ncbi.nlm.nih.gov/pubmed/20604606">and girls</a> by society. In other words, no biological or genetic study has concluded that nature is stronger than nurture.</p>
<h2>How free are we really?</h2>
<p>The researchers behind the new study explain their results by referring to the <a href="https://www.hse.ru/data/2013/02/20/1306830406/Inglehart&amp;Norris_Rising%2520Tide.pdf">theory of post-materialism</a>. This says that once material needs are satisfied, human beings are free to make their own decisions and express themselves however they want. In poorer countries, men and women are more equally involved in simply making enough money to get by so they aren’t free in this way. In rich countries, more resources supposedly provide more scope for expressing intrinsic gender preferences and behaviour.</p>
<p>What I think the study actually shows is that economic equality leaves men and women freer to express the gender differences that have been created in them by social pressures. This is the same conclusion recently reached by Paul Polman, chief executive officer of Unilever, <a href="https://www.weforum.org/agenda/2017/11/why-is-gender-equality-in-decline-and-how-can-we-reverse-it/">when discussing</a> the <a href="http://www3.weforum.org/docs/WEF_GGGR_2017.pdf">2017 World Economic Forum Global Gender Gap report</a> (the same report used as a measure of gender equality in the new study).</p>
<p>If we really want to understand what drives gender inequality we should ask people who they think are the most caring and most successful people they know. Then we should count how many times women and men are named in these respective roles, by men and women respectively. They will show us how much traditional beliefs about gender roles are still in place, even more in supposedly rich and equal countries.</p><img src="https://counter.theconversation.com/content/105424/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Elisa Bellotti ne travaille pas, ne conseille pas, ne possède pas de parts, ne reçoit pas de fonds d&#39;une organisation qui pourrait tirer profit de cet article, et n&#39;a déclaré aucune autre affiliation que son poste universitaire.</span></em></p>Gender differences in jobs and attitudes are wider in countries with more equality, but that's not the end of the story.Elisa Bellotti, Senior Lecturer in Sociology, University of ManchesterLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/989032018-06-26T13:46:18Z2018-06-26T13:46:18ZTestosterone levels determined by where men grow up – new research<figure><img src="https://images.theconversation.com/files/224902/original/file-20180626-112634-1230x62.jpg?ixlib=rb-1.1.0&amp;rect=1%2C0%2C997%2C615&amp;q=45&amp;auto=format&amp;w=496&amp;fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><a class="source" href="https://www.shutterstock.com/download/confirm/517918024?src=VPQuOAgdmZrMXmm7wGgjww-1-38&amp;size=medium_jpg">FOTOKITA/Shutterstock.com</a></span></figcaption></figure><p>Boys who grow up in healthier, wealthier environments tend to have more testosterone as adults, our <a href="https://rdcu.be/1UX8">latest research</a> shows. </p>
<p>Previous research tells us that average levels of testosterone vary widely, <a href="https://academic.oup.com/humrep/article/17/12/3251/569620">depending on where men live</a>. Men in wealthier countries tend to have higher levels of testosterone than men in poorer countries or places with high rates of infectious disease.</p>
<p>What this earlier research didn’t tell us was whether these differences were due to how men reacted to their immediate surroundings as adults, or whether these differences were set prior to adulthood, or even in infancy. </p>
<p>Our study, published in Nature Ecology and Evolution, supports the idea that the environment a man grows up in affects his testosterone levels later in his life. But our results suggest that this “setting” of adult testosterone levels doesn’t occur in infancy, but is determined in later childhood.</p>
<h2>Sylhet and East London</h2>
<p>The groups we studied trace their heritage to Sylhet in Bangladesh, a region with a history of migration to London for three generations. They settled in relatively culturally similar, densely populated neighbourhoods of East London. In other words, the lifestyles of these two groups was fairly similar. Our goal was to compare testosterone levels, height and age at puberty depending on the environment where a man spent his childhood. </p>
<p>Access to healthcare is limited in Sylhet and urban sanitation is poor. We consider this one of the clearest contrasts between growing up in Sylhet, Bangladesh and London. We compared 59 men who migrated from Sylhet to London as children, 75 who migrated as adults, 107 men who lived in Sylhet all their lives, 56 men born in London with Sylheti parents, and 62 men of European ethnicity from London. </p>
<h2>Life history theory</h2>
<p>A guiding idea for our project was <a href="https://medanth.wikispaces.com/Life+History+Theory">life history theory</a>, an evolutionary theory that sees the energy available over the lifetime of an organism as something like a budget. For example, energy spent on efforts like fighting disease can’t be invested in other energetically costly endeavours, such as growing taller, heavier or more muscular. </p>
<p>We found that the longer a man lived in Bangladesh as a child, the shorter he was as an adult. This suggests that boys growing up in Bangladesh had to trade off growing taller for something else, such as immunity. </p>
<p>If they were taking in less energy from food or were spending more on physical labour, this might also explain the differences in height. But the men we measured mostly grew up in the city, not farms, and were from well-off families, by Bangladeshi standards, with ready access to food when they were growing up, so we think energy spent on fighting disease is the biggest cost when considering these differences in growth.</p>
<p>We consider testosterone as a marker of how much a man has invested in reproduction. Testosterone has costs in terms of muscle and metabolism, and potentially shapes competitive behaviour, so men apparently trade off these costs based on their childhood environment. </p>
<p>We think that the energy budgeted for reproduction throughout life is determined at some point in later childhood, and that once a male “commits” a proportion of his investment to reproduction, it determines his regular levels of testosterone for the rest of his adult life. </p>
<h2>Implications for health</h2>
<p>Our findings have important implications for healthcare. <a href="https://onlinelibrary.wiley.com/doi/full/10.1002/ajpa.10025">Testosterone is associated</a> with growth of muscle, libido and the functioning of male reproductive organs, including the prostate. It’s possible that the change in environment for migrants from Bangladesh to the UK means they will have greater risk of diseases of the prostate. </p>
<p>Also, the UK-born children of Bangladeshi migrants had higher levels of testosterone than men with non-migrant parents, suggesting that children of migrants may adjust their trade offs in different ways than children of non-migrants. These men may be at greater risk of enlargement of the prostate in later life, and may need to be especially aware of screening programmes for prostate disease. </p>
<p>The next step is to see if these children of migrants have higher incidence of symptoms related to prostate disease, for instance <a href="https://prostatecanceruk.org/prostate-information/further-help/enlarged-prostate">benign prostate hyperplasia</a>.</p>
<h2>Similar pattern in women</h2>
<p>Our work emerged from previous research with Bangladeshi migrant women. Women <a href="http://journals.plos.org/plosmedicine/article?id=10.1371/journal.pmed.0040167">had higher levels of the reproductive steroid progesterone</a> if they migrated to the UK as children. </p>
<p>Since then there have been a number of other studies of women’s health, that suggest these trade offs made in early life determine a host of different characteristics relating to women’s fertility and the timing of a woman’s <a href="https://breast-cancer-research.biomedcentral.com/articles/10.1186/s13058-014-0469-8">reproductive lifespan</a>. So it appears that living in the UK – or other wealthy country – increases the amount a person budgets to reproduction, whether they are a man or woman.</p><img src="https://counter.theconversation.com/content/98903/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Kesson Magid received funding for this research from the Economic and Social Research Council UK. </span></em></p>Better childhood environments linked with higher testosterone levels in later life.Kesson Magid, Research Associate in the Department of Anthropology, Durham UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/943902018-04-08T19:55:16Z2018-04-08T19:55:16ZA sexist policy may end the career of one of the Commonwealth's greatest female runners<p>South African superstar Caster Semenya is poised this week to become the third woman in the history of the Commonwealth Games to win double gold in the 800-metre and 1500-metre races. But a <a href="https://www.iaaf.org/news/press-release/birmingham-council-meeting-day-2">new policy</a> on hyperandrogenism (characterised by high testosterone) may spell the end of her illustrious career. </p>
<p>The policy from the International Association of Athletics Federations (IAAF), which council members approved last month and takes effect in November, is suspiciously selective. It applies only to women who compete in track events between 400 and 1500 metres. These are the distances at which Semenya excels. </p>
<p>Weighed against other testosterone-related regulations, the new policy is not only confusing but also contradictory. Even more, the regulations suggest that testosterone is a luxury only men can afford.</p>
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<a href="http://theconversation.com/the-price-of-victory-caster-semenya-again-on-trial-64366">The price of victory: Caster Semenya again on trial</a>
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<p>The IAAF’s latest policy stems from an 2017 IAAF-funded <a href="https://www.ncbi.nlm.nih.gov/pubmed/28673896">study</a> (critiqued <a href="http://bjsm.bmj.com/content/bjsports/early/2018/01/18/bjsports-2017-098446.full.pdf">here</a>). Researchers found that elite female competitors with higher testosterone “have a significant competitive advantage” over those with lower testosterone in five events: the 400-metre race (2.7% advantage), 400-metre hurdles (2.8% advantage), 800-metre race (1.8%), hammer throw (4.5%) and pole vault (2.9%). </p>
<p>Yet, without explanation, the new guidelines omit both the pole vault and hammer throw, where high-testosterone women ostensibly enjoy the greatest advantage, and add the women’s 1500-metre race, even though it was not one of the events in which testosterone seemed to matter. The hormone, the study concluded, <a href="https://www.ncbi.nlm.nih.gov/pubmed/28673896">does not affect</a> men in “any of the male athletic events”. </p>
<h2>Defining ‘femaleness’ in sport</h2>
<p>Policies that regulate women’s testosterone are part of a <a href="https://www.press.uillinois.edu/books/catalog/85fcr3nh9780252040221.html">long history</a> of athletics authorities attempting to establish some definitive marker of “femaleness”. </p>
<p>It began in the 1930s, not long after women started <a href="https://www.press.uillinois.edu/books/catalog/58ctr3rx9780252038167.html">competing internationally</a> in track and field. Consumed with the need to verify femaleness (but never maleness), officials moved from <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3007680/">medical certificates</a> in the 1940s, to gynaecological exams and visual inspections in 1966, <a href="https://jamanetwork.com/journals/jama/article-abstract/344138">chromosome tests</a> from 1967 until 1992, and <a href="http://bjsm.bmj.com/content/30/4/310.short">genetic testing</a> from 1992 to 1999. </p>
<p>Each iteration of sex testing ultimately proved costly, damaging, discriminatory and ineffective. Consequently, authorities decided to stop testing all women and, instead, tested only those who seemed “<a href="https://ihra.org.au/wp-content/uploads/2009/01/iaaf_policy_on_gender_verification.pdf">suspcious</a>”. </p>
<p>This is apparently what happened to Semenya who, quite publicly, underwent “<a href="https://www.iaaf.org/news/news/statement-on-caster-semenya">gender verification</a>” procedures at the 2009 World Championships. Although she has never confirmed that she has <a href="http://www.abc.net.au/news/2009-09-11/semenya-maybe-not-100pc-a-woman/1424994">elevated testosterone</a>, the IAAF’s first <a href="https://www.iaaf.org/news/iaaf-news/iaaf-to-introduce-eligibility-rules-for-femal-1">policy</a> on hyperandrogenism, published in 2011, appeared to be a direct response to the controversy that surrounded her. </p>
<p>This 2011 policy required any female athlete who showed “high” levels of functional testosterone (10 or more nanomoles per litre of serum, to be exact), regardless of event, to either lower those levels or drop out of sport. </p>
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<p>Indian sprinter Dutee Chand rejected both options. <a href="https://www.hindustantimes.com/other-sports/dutee-chand-free-to-compete-as-iaaf-s-appeal-temporarily-suspended/story-Nbzy3japotIgkIg959B7qO.html">Barred</a> from the 2014 Commonwealth Games on a diagnosis of hyperandrogenism, she <a href="https://www.nytimes.com/2014/10/07/sports/sprinter-dutee-chand-fights-ban-over-her-testosterone-level.html">challenged</a> her disqualification in the Court of Arbitration for Sport (CAS). </p>
<p>There, arbitrators ruled that the IAAF had not shown sufficient evidence linking high testosterone to enhanced performance and could not, therefore, enforce its policy on hyperandrogenism. CAS gave the IAAF two years to prove its case.</p>
<p>This allowed Chand to compete at the 2016 Olympics, where she failed to qualify for the semi-finals of the 100-metre race. She also failed to qualify for this year’s Commonwealth Games. Testosterone may relate to enhanced performance, but it’s not a silver bullet (or bronze or gold, for that matter).</p>
<p>Semenya, in contrast, <a href="https://www.reuters.com/article/us-olympics-rio-athletics-w-800m/south-africas-semenya-takes-800-meters-gold-idUSKCN10W00L">won</a> the 800-metre race in Rio and has added the <a href="http://www.cbc.ca/sports/olympics/trackandfield/caster-semenya-nationals-south-africa-1.3539140">400-metre and 1500-metre</a> events to her impressive repertoire. </p>
<p>In the meantime, the IAAF scrambled to find enough evidence to dismiss Chand’s case with CAS, which is precisely what the new regulations do.</p>
<h2>How do you solve a problem like testosterone?</h2>
<p>Athletic authorities have never worried about the need to define “maleness” and, aside from doping, appear unconcerned with men’s testosterone. Indeed, if a male athlete exceeded the “normal” hormonal reference range, he’d likely be revered as one studly specimen. </p>
<p>During Chand’s trial, lawyers asked Dr. Stéphane Bermon, a co-author of the 2017 study underpinning the new policy, why male athletes weren’t subjected to similar testing. </p>
<p>He <a href="http://www.tas-cas.org/fileadmin/user_upload/AWARD_3759__FINAL___REDACTED_FOR_PUBLICATION_.pdf">responded</a> that the question was pointless because there is no third “super male” category in sport. Women with too much testosterone aren’t “super female”, they are men – at least according to the International Olympic Committee’s 2015 “<a href="https://stillmed.olympic.org/Documents/Commissions_PDFfiles/Medical_commission/2015-11_ioc_consensus_meeting_on_sex_reassignment_and_hyperandrogenism-en.pdf">consensus statement</a>”, which recommends that hyperandrogenic women “not eligible for female competition… should be eligible to compete in male competition”.</p>
<p>No one suggests that men with low testosterone should be eligible for female competition.</p>
<p>In fact, the World Anti-Doping Agency (WADA) allows men diagnosed with low testosterone to apply for <a href="https://www.asada.gov.au/therapeutic-use-exemption">an exemption</a> to take synthetic testosterone, an otherwise banned substance, because they have a <a href="https://www.wada-ama.org/en/resources/therapeutic-use-exemption-tue/medical-information-to-support-the-decisions-of-tuecs-male">medical need</a>.</p>
<p>In the same document, WADA stipulates (in bold font) that this exception “should not be approved for females”. Even if a woman’s testosterone falls below a healthy limit, she is not granted the same opportunity as a man to raise it to levels commensurate with her same-sex competitors. </p>
<p>Trans male athletes (who transition from female to male), however, can compete hormonally unfettered. In fact, WADA maintains that <a href="https://www.wada-ama.org/sites/default/files/resources/files/wada-tpg-medical-info-female-to-male-transsexual-athletes_1.3_en.pdf">the use of synthetic testosterone</a> “is essential for completion of the anatomical and psychological transition process in female-to-male athletes”. </p>
<p>This means that testosterone is not just about performance enhancement, but also about one’s health and wellbeing. But only when it comes to men.</p>
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<strong>
Read more:
<a href="http://theconversation.com/why-it-might-be-time-to-eradicate-sex-segregation-in-sports-89305">Why it might be time to eradicate sex segregation in sports</a>
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<p>In a <a href="https://www.wada-ama.org/sites/default/files/resources/files/wada_transgender_athletes_v1.0_en.pdf">separate document</a>, WADA insists that “there is no known indication for testosterone supplementation in transgender female athletes”. </p>
<p>Not true, <a href="http://www.sportsintegrityinitiative.com/worleys-case-opens-courts-athlete-human-rights-cases/">says</a> cyclist Kristen Worley and, in 2017, the Human Rights Tribunal of Ontario in Canada <a href="http://www.hrlsc.on.ca/sites/default/files/docs/en/Media/2017-07-06%20%20Worley%20v%20%20OCA%20%20CC%20MOS%20public.pdf">concurred</a>. </p>
<p>Worley, who prefers the term XY female, produces almost no natural testosterone (or oestrogen, for that matter) as a result of gender confirmation surgery. She charged three major cycling bodies, including the Union Cycliste Internationale, with sex discrimination for not allowing her the sufficient use of synthetic testosterone during her racing career. </p>
<p>This wasn’t merely a sport issue, Worley <a href="http://www.sportsintegrityinitiative.com/testosterone-is-not-exclusively-a-male-hormone/">explained</a>. Testosterone is responsible for “over 200 daily functions in the human body”, and she was in “complete hormone deprivation”. </p>
<p>In the end, the cycling federations <a href="http://www.uci.ch/pressreleases/cycling-canada-ontario-cycling-association-the-union-cycliste-internationale-uci-and-canadian-athlete-kristen-worley-settle-human-rights-application-promote-inclusive-sporting-environments/">agreed</a> to review and revise their regulations and “adopt policies and guidelines that are based in objective scientific research”. Not a bad idea. Perhaps the IAAF should consider a similar commitment. </p>
<p>Until then, we may be left with a sport without Caster Semenya, or at least the same Caster Semenya who continues to set new standards of excellence in women’s track and field. </p>
<p>Underneath all this are questions about whether and how to maintain sex segregation in sport. Since the 1930s, sport has made a mess of sex. Maybe it’s time sex made a mess of sport. Come to think of it, it already has.</p><img src="https://counter.theconversation.com/content/94390/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Jaime Schultz does not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>A new policy may spell the end of Caster Semenya's illustrious running career.Jaime Schultz, Associate Professor of Kinesiology, Pennsylvania State UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/825872017-10-23T03:41:12Z2017-10-23T03:41:12ZHealth Check: do boys really have a testosterone spurt at age four?<figure><img src="https://images.theconversation.com/files/182699/original/file-20170821-20193-p8clu9.jpg?ixlib=rb-1.1.0&amp;q=45&amp;auto=format&amp;w=496&amp;fit=clip" /><figcaption><span class="caption">There&#39;s lots going on in the lives of four-year-old boys, including how to regulate their emotions. Let&#39;s not blame their hormones.</span> <span class="attribution"><a class="source" href="https://www.shutterstock.com/download/confirm/594435866?src=vUIze5kpCfgxwZaN2ReyJg-1-54&amp;size=medium_jpg">from www.shutterstock.com</a></span></figcaption></figure><p>The idea that four-year-old boys have a spurt of testosterone is <a href="http://www.powerfulmothering.com/that-tricky-thing-called-testosterone/">often used to explain</a> challenging behaviour at this age.</p>
<p>But how did this idea come about? Is there any truth in it? And if not, what else could explain their behaviour?</p>
<hr>
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<em>
<strong>
Read more:
<a href="http://theconversation.com/helicopter-snowplow-or-free-range-whats-your-parenting-style-15123">Helicopter, snowplow or free range – what's your parenting style?</a>
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<p>Psychologist and author Stephen Biddulph <a href="http://www.canberratimes.com.au/preschoolers/preschooler-development/when-testosterone-kicks-in-for-young-boys-20140625-3asn6.html">is often credited</a> with being the source of the idea that four-year-old boys have a testosterone spurt.</p>
<p>Although he mentioned it in his bestselling book <a href="http://finch.com.au/books/steve-biddulphs-raising-boys-4th-edition">Raising Boys</a>, he was writing about someone else’s work:</p>
<blockquote>
<p>According to Professor Mitchell Harman in the US Department of Aging, boys undergo a testosterone burst at age four … Not all researchers have agreed with this finding though, so it remains controversial.</p>
</blockquote>
<p>Biddulph said Professor Harman wrote about this for an article in the men’s magazine Esquire in 1999 and “stood by these findings” when contacted in 2015.</p>
<h2>So, what does the evidence say?</h2>
<p>As a researcher and adolescent endocrinologist, who specialises in puberty hormones, I can say there is no evidence this testosterone spurt exists. Many studies of hormones in boys in peer-reviewed journals <a href="http://www.tandfonline.com/doi/abs/10.3109/00365513.2014.942694">confirm</a> <a href="https://www.karger.com/Article/Pdf/358560">this</a>.</p>
<p><a href="https://www.news-medical.net/health/Testosterone-Physiological-Effects.aspx">Raised levels of testosterone</a> are not possible when testes (where testosterone is made) are small and levels of the hormone that stimulates testosterone production is low.</p>
<p>The only time when a four-year-old’s testosterone level is high is in a serious and uncommon condition called <a href="http://www.msdmanuals.com/en-au/professional/pediatrics/endocrine-disorders-in-children/precocious-puberty">precocious puberty</a>, where boys enter puberty and their testicles enlarge much earlier than usual.</p>
<h2>Yes, testosterone rises, but not at this age</h2>
<p>There are rises in testosterone during a boy’s development, which coincide with <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2989000">major brain development</a>. But these don’t happen at the age of four.</p>
<p>Testosterone first increases to puberty-like levels in boys during the <a href="https://www.womenshealth.gov/pregnancy/youre-pregnant-now-what/stages-pregnancy">first two trimesters of pregnancy</a>. This testosterone is responsible for the development of the penis and scrotum, a process known as the <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3443292">masculinisation of external genitalia</a>.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="http://theconversation.com/heres-what-you-need-to-know-about-testosterone-31687">Here's what you need to know about testosterone</a>
</strong>
</em>
</p>
<hr>
<p>The second testosterone increase occurs in the first six months or so of life. This <a href="https://link.springer.com/content/pdf/10.1007/978-1-4419-1795-9_39.pdf">mini-puberty</a> results in boys’ genitalia briefly looking more prominent, which many parents notice.</p>
<p>Puberty is the third and final rise in testosterone, with levels increasing 10- to 20-fold over two to three years. Puberty is a time of major physical growth accompanied by <a href="http://www.jneurosci.org/content/35/40/13539">significant behaviour changes</a>, clearly influenced by brain development. </p>
<h2>Yes, there are hormone changes, but not testosterone</h2>
<p>There are hormone changes starting at around five to six years in both sexes in a period known as <a href="https://www.ncbi.nlm.nih.gov/pubmed/21164255">adrenarche</a>. Perhaps this has also contributed to the confusion.</p>
<p>Adrenarche is the maturation of part of the adrenal glands where hormones similar to, but much weaker than, testosterone are made. Their most common effect is <a href="https://www.ncbi.nlm.nih.gov/pubmed/21164255">body odour</a>. However, researchers don’t know why exactly boys and girls have this phase. And no-one has yet seen any clear effects on childhood behaviour.</p>
<h2>No, testosterone doesn’t spurt</h2>
<p>Use of the word “<a href="https://en.oxforddictionaries.com/definition/spurt">spurt</a>” to describe testosterone production is also incorrect. </p>
<p>Testosterone does not spurt at any time of life. The word “spurt” creates a sense of rapidity and urgency, giving testosterone a reputation in childhood it does not deserve. Instead, when testosterone levels rise in puberty, it <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4949545/">increases gradually at first, then accelerates in mid to late puberty</a>.</p>
<h2>So, what else can explain behaviour?</h2>
<p>So is there an alternative explanation for boys’ behaviour at this age, which parents regularly report?</p>
<p>We see differences in boys’ and girls’ <a href="https://www.ncbi.nlm.nih.gov/pubmed/20826305">brains</a> and <a href="https://link.springer.com/article/10.1007/s00424-013-1268-2">behaviour</a> well before puberty. Rises in testosterone in the womb and during the mini-puberty in the first six months of life likely explain these. </p>
<p>Studies that look at behaviour in four to five-year-olds tend to focus on play and social interactions, because these are what children this age do most of the time.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/187718/original/file-20170927-24193-1rt2joc.jpg?ixlib=rb-1.1.0&amp;q=45&amp;auto=format&amp;w=1000&amp;fit=clip"><img alt="" src="https://images.theconversation.com/files/187718/original/file-20170927-24193-1rt2joc.jpg?ixlib=rb-1.1.0&amp;q=45&amp;auto=format&amp;w=754&amp;fit=clip" srcset="https://images.theconversation.com/files/187718/original/file-20170927-24193-1rt2joc.jpg?ixlib=rb-1.1.0&amp;q=45&amp;auto=format&amp;w=600&amp;h=400&amp;fit=crop&amp;dpr=1 600w, https://images.theconversation.com/files/187718/original/file-20170927-24193-1rt2joc.jpg?ixlib=rb-1.1.0&amp;q=30&amp;auto=format&amp;w=600&amp;h=400&amp;fit=crop&amp;dpr=2 1200w, https://images.theconversation.com/files/187718/original/file-20170927-24193-1rt2joc.jpg?ixlib=rb-1.1.0&amp;q=15&amp;auto=format&amp;w=600&amp;h=400&amp;fit=crop&amp;dpr=3 1800w, https://images.theconversation.com/files/187718/original/file-20170927-24193-1rt2joc.jpg?ixlib=rb-1.1.0&amp;q=45&amp;auto=format&amp;w=754&amp;h=503&amp;fit=crop&amp;dpr=1 754w, https://images.theconversation.com/files/187718/original/file-20170927-24193-1rt2joc.jpg?ixlib=rb-1.1.0&amp;q=30&amp;auto=format&amp;w=754&amp;h=503&amp;fit=crop&amp;dpr=2 1508w, https://images.theconversation.com/files/187718/original/file-20170927-24193-1rt2joc.jpg?ixlib=rb-1.1.0&amp;q=15&amp;auto=format&amp;w=754&amp;h=503&amp;fit=crop&amp;dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Boys and girls this age tend to have different styles of play.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/download/confirm/245148427?src=PgfeMmrAnQHDwA_WguLr5w-1-52&amp;size=medium_jpg">from www.shutterstock.com</a></span>
</figcaption>
</figure>
<p>Such studies show boys and girls this age generally have <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2951011/">different ways of playing and communicating</a>. Boys’ play is generally more physical, engaging with mobile toys or building structures. Girls generally have more socially interactive play, and are more articulate. </p>
<p>Interestingly, girls with <a href="https://www.rch.org.au/uploadedFiles/Main/Content/MedEd/fracp/CAH%20PIR%202009.pdf">congenital adrenal hyperplasia</a>, when they are exposed to high levels of testosterone in the womb, tend to have more “<a href="https://www.ncbi.nlm.nih.gov/pubmed/12760514">rough and tumble</a>” play styles, consistent with a testosterone effect on early brain development.</p>
<h2>So, how might being four or five change boys’ behaviour?</h2>
<p>At this age, children <a href="http://raisingchildren.net.au/preschoolers/preschoolers.html">learn how to</a> interact with others, understand another’s needs, share, and to deal with new and unfamiliar situations.</p>
<p>So, children must learn to <a href="https://www.kidsmatter.edu.au/early-childhood/resources-support-childrens-mental-health/about-emotions/self-regulation">regulate their own emotions</a>, like fear, concern, upset and anger. </p>
<p>When children don’t do this, we see the emotional outbursts, which can be explosive. Children can struggle to either understand or articulate why they lost control of their emotions. Boys <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2951011/">may respond</a> more physically and be less able to articulate what happened.</p>
<hr>
<p>
<em>
<strong>
Read more:
<a href="http://theconversation.com/talking-to-kids-about-emotions-matters-more-than-you-think-21955">Talking to kids about emotions matters more than you think</a>
</strong>
</em>
</p>
<hr>
<p>Learning how to regulate their emotions is an important skill for children to develop. Parents can <a href="https://www.kidsmatter.edu.au/early-childhood/resources-support-childrens-mental-health/social-development">model good emotional regulation</a>, make sure children have regular daily routines, enough time to practice play and <a href="https://www.ncbi.nlm.nih.gov/pubmed/28129449">enough sleep</a>. Praising positive behaviour and not overreacting to minor attention-seeking misbehaviour also helps.</p>
<p>We shouldn’t blame hormones for children’s behaviour. Instead, we need to better understand those behaviours.</p>
<p>For instance, persistent and distressing behaviours in a child may signal underlying anxieties, reaction to family stresses, which are felt but not understood, or be a result of <a href="http://jamanetwork.com/journals/jamapediatrics/fullarticle/2427470">adversities when they were younger</a>. So, if you are concerned, seek professional advice.</p>
<p>For all children, we need to prioritise <a href="https://www.cam.ac.uk/news/world-leading-academic-appointed-to-lead-play-research-centre">time to play</a>. That could mean space, action and permission to be noisy and boisterous.</p>
<hr>
<p><em>For more information about behaviour in preschoolers see the <a href="http://raisingchildren.net.au/preschoolers/preschoolers.html">Raising Children Network</a>. If you are concerned about your preschooler’s behaviour and want support, see <a href="https://healthyfamilies.beyondblue.org.au/age-1-5?&amp;gclid=EAIaIQobChMIi4ei4eCh1gIVhggqCh3VdgheEAMYASAAEgJR5_D_BwE">beyondblue</a>.</em></p><img src="https://counter.theconversation.com/content/82587/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Kate Steinbeck does not work for, consult, own shares in or receive funding from any company or organization that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>Some parents think their four-year-old boy's emotional outbursts and aggressive behaviour can be blamed on their hormones. Here's why that's a myth.Kate Steinbeck, Medical Foundation Chair in Adolescent Medicine, University of SydneyLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/828762017-09-04T23:54:27Z2017-09-04T23:54:27ZFinger size does matter... in sports<figure><img src="https://images.theconversation.com/files/184233/original/file-20170831-32045-1vl98iu.jpg?ixlib=rb-1.1.0&amp;q=45&amp;auto=format&amp;w=496&amp;fit=clip" /><figcaption><span class="caption">While this football player&#39;s arms may look like they give him an onfield advantage, his fingers may actually be more predictive of his athletic ability.</span> <span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/american-football-player-man-isolated-519472111?src=OjIGXD_TCH184vwa52BeLg-1-30">Ostill/Shutterstock.com </a></span></figcaption></figure><p>Examine your fingers. Which is longer? Is it the index finger (the finger you use to point with – technically the second digit, or 2D, counting the thumb), or the ring finger (the fourth digit, or 4D)?</p>
<p>The relative length of the index and ring fingers is known as the <a href="https://en.wikipedia.org/wiki/Digit_ratio">digit ratio</a> or the 2D:4D. For example, if your index finger is 2.9 inches (or 7.4 cm) long, and your ring finger is 3.1 inches (or 7.9 cm) long, your digit ratio is 0.935 (i.e., 2.9/3.1 or 7.4/7.9).</p>
<p><a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3182741/">Males typically have lower digit ratios</a> (the ring finger in males is typically longer than the index finger) than females (the fingers are about the same length in females). The ratio <a href="https://www.ncbi.nlm.nih.gov/pubmed/16040033">does not change much with age</a>.</p>
<figure class="align-right ">
<img alt="" src="https://images.theconversation.com/files/183668/original/file-20170829-12314-k717ts.jpg?ixlib=rb-1.1.0&amp;q=45&amp;auto=format&amp;w=237&amp;fit=clip" srcset="https://images.theconversation.com/files/183668/original/file-20170829-12314-k717ts.jpg?ixlib=rb-1.1.0&amp;q=45&amp;auto=format&amp;w=600&amp;h=633&amp;fit=crop&amp;dpr=1 600w, https://images.theconversation.com/files/183668/original/file-20170829-12314-k717ts.jpg?ixlib=rb-1.1.0&amp;q=30&amp;auto=format&amp;w=600&amp;h=633&amp;fit=crop&amp;dpr=2 1200w, https://images.theconversation.com/files/183668/original/file-20170829-12314-k717ts.jpg?ixlib=rb-1.1.0&amp;q=15&amp;auto=format&amp;w=600&amp;h=633&amp;fit=crop&amp;dpr=3 1800w, https://images.theconversation.com/files/183668/original/file-20170829-12314-k717ts.jpg?ixlib=rb-1.1.0&amp;q=45&amp;auto=format&amp;w=754&amp;h=795&amp;fit=crop&amp;dpr=1 754w, https://images.theconversation.com/files/183668/original/file-20170829-12314-k717ts.jpg?ixlib=rb-1.1.0&amp;q=30&amp;auto=format&amp;w=754&amp;h=795&amp;fit=crop&amp;dpr=2 1508w, https://images.theconversation.com/files/183668/original/file-20170829-12314-k717ts.jpg?ixlib=rb-1.1.0&amp;q=15&amp;auto=format&amp;w=754&amp;h=795&amp;fit=crop&amp;dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">The digit ratio is calculated by measuring the lengths of the index and ring fingers from the midpoint of the lowest crease (where they join the hand) to the fingertip, and then by dividing the index finger length by the ring finger length.</span>
<span class="attribution"><span class="source">Grant Tomkinson, author provided</span></span>
</figcaption>
</figure>
<p>There is some indirect evidence that the digit ratio is determined during early fetal development – as early as the second trimester of pregnancy – by the <a href="https://www.ncbi.nlm.nih.gov/pubmed/15113628">balance between the steroid hormones</a> testosterone and estrogen. The developing ring finger has a high number of receptors for testosterone: the more testosterone the fetus produces, the longer the ring finger, and so the lower the digit ratio.</p>
<p>Our research team wanted to take this finger research a step further: could the differences predict athletic ability, and, if so, how? </p>
<h2>Digit ratios and sports</h2>
<p>In general, those with lower digit ratios – that is, those whose ring fingers are relatively longer than their pointers – are <a href="http://www.sciencedirect.com/science/article/pii/S0191886909003560">more likely to perform better</a> across a very wide range of sports and athletic events. This was first illustrated in a <a href="https://www.ncbi.nlm.nih.gov/pubmed/11182575">detailed study</a> of English professional football (soccer) players.</p>
<p>In 2001, researchers John Manning and Rogan Taylor showed that professional football players had lower digit ratios than nonathletes, first team players had lower ratios than reserve or youth team players, footballers who played for their country had lower ratios than those who hadn’t and those who played for their country more often (more caps) had lower ratios than those who played less often.</p>
<p>Although considerable variability exists across different activities, subsequent research has shown that people with low digit ratios tend to be better at <a href="http://web.b.ebscohost.com/abstract?direct=true&amp;profile=ehost&amp;scope=site&amp;authtype=crawler&amp;jrnl=18690459&amp;AN=95028744&amp;h=KBcXpBzlyogrGmUAw7RDhAQx7R1XCdetxXpCHfHrsLPLzqHFSCdVO8SCcfGgpmdp6Q0CZLIbe85iotIGpib2uQ%3d%3d&amp;crl=c&amp;resultNs=AdminWebAuth&amp;resultLocal=ErrCrlNotAuth&amp;crlhashurl=login.aspx%3fdirect%3dtrue%26profile%3dehost%26scope%3dsite%26authtype%3dcrawler%26jrnl%3d18690459%26AN%3d95028744">American football (gridiron)</a>, <a href="https://www.ncbi.nlm.nih.gov/pubmed/28504855">basketball</a>, <a href="https://www.ncbi.nlm.nih.gov/pubmed/19843265">fencing</a>, <a href="https://www.ncbi.nlm.nih.gov/pubmed/23444944">handball</a>, <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4267485/">kabaddi</a> (an Indian contact sport), <a href="https://www.ncbi.nlm.nih.gov/pubmed/25242253">rowing</a>, <a href="https://www.ncbi.nlm.nih.gov/pubmed/20981610">rugby</a>, running (both <a href="https://www.ncbi.nlm.nih.gov/pubmed/19107924">sprinting</a> and <a href="https://www.ncbi.nlm.nih.gov/pubmed/17420996">cross-country</a>), <a href="https://www.ncbi.nlm.nih.gov/pubmed/12391439">slalom skiing</a>, <a href="http://www.sciencedirect.com/science/article/pii/S1090513811000705">sumo wrestling</a>, <a href="https://www.ncbi.nlm.nih.gov/pubmed/21993037">surfing</a>, <a href="https://www.ncbi.nlm.nih.gov/pubmed/25068756">swimming</a>, <a href="https://www.ncbi.nlm.nih.gov/pubmed/25226321">tennis</a> and <a href="http://www.scopemed.org/?mno=44287">volleyball</a>.</p>
<p>While the relationship between digit ratio and sports performance is generally stronger in males than in females, important relationships have been seen in females. For example, we published <a href="https://www.ncbi.nlm.nih.gov/pubmed/25242253">a study</a> in 2015 showing that females with lower ratios rowed substantially faster at the Australian Rowing Championships than females with higher ratios.</p>
<p>The relationships have also generally been stronger for athletes who compete in closed-skill sports (stable, predictable, self-paced environments such as rowing, running, swimming) than athletes who compete in open-skill sports (unstable, unpredictable, externally paced environments such as basketball, football, volleyball). This is probably because single traits, such as the digit ratio, are not usually favorably related to open-skill sports performance because numerous factors determined by the collective actions of all players, not the individual, are involved in sporting success.</p>
<p>Nonetheless, in <a href="https://www.ncbi.nlm.nih.gov/pubmed/28504855">a recent study</a> of Australian basketball players, we showed that men with lower ratios were more likely to reach higher competitive levels and play at the Olympic Games.</p>
<figure class="align-right ">
<img alt="" src="https://images.theconversation.com/files/183683/original/file-20170829-14211-1e9eadv.jpg?ixlib=rb-1.1.0&amp;q=45&amp;auto=format&amp;w=237&amp;fit=clip" srcset="https://images.theconversation.com/files/183683/original/file-20170829-14211-1e9eadv.jpg?ixlib=rb-1.1.0&amp;q=45&amp;auto=format&amp;w=600&amp;h=961&amp;fit=crop&amp;dpr=1 600w, https://images.theconversation.com/files/183683/original/file-20170829-14211-1e9eadv.jpg?ixlib=rb-1.1.0&amp;q=30&amp;auto=format&amp;w=600&amp;h=961&amp;fit=crop&amp;dpr=2 1200w, https://images.theconversation.com/files/183683/original/file-20170829-14211-1e9eadv.jpg?ixlib=rb-1.1.0&amp;q=15&amp;auto=format&amp;w=600&amp;h=961&amp;fit=crop&amp;dpr=3 1800w, https://images.theconversation.com/files/183683/original/file-20170829-14211-1e9eadv.jpg?ixlib=rb-1.1.0&amp;q=45&amp;auto=format&amp;w=754&amp;h=1207&amp;fit=crop&amp;dpr=1 754w, https://images.theconversation.com/files/183683/original/file-20170829-14211-1e9eadv.jpg?ixlib=rb-1.1.0&amp;q=30&amp;auto=format&amp;w=754&amp;h=1207&amp;fit=crop&amp;dpr=2 1508w, https://images.theconversation.com/files/183683/original/file-20170829-14211-1e9eadv.jpg?ixlib=rb-1.1.0&amp;q=15&amp;auto=format&amp;w=754&amp;h=1207&amp;fit=crop&amp;dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Tomkinson’s son, Jordan, playing high school basketball for the Sacred Heart Eagles (East Grand Forks, Minnesota), author provided.</span>
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<p>Another interesting finding is that the right digit ratio is apparently more sensitive to fetal steroid hormones than is the left digit ratio. This might be why the right ratio is sometimes better related to athletic performance. </p>
<h2>Why are people with lower digit ratios better athletes?</h2>
<p>While the digit ratio itself does not confer a sporting advantage, it is thought to be a biomarker of fetal testosterone, which has powerful, long-term effects on the developing body and brain. For example, it influences the growth and development of several organs, including the brain, heart, muscles and bones, which are important for sports and athletic performance. </p>
<p>Studies have shown that people with lower digit ratios tend to have better <a href="https://www.ncbi.nlm.nih.gov/pubmed/11182575">visual-spatial</a> and <a href="http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0046319">cognitive ability</a>, presumably due to better development of the right side of the brain. These abilities are important in sports where athletes have to follow the flight of the ball, read the play and make tactical decisions. </p>
<p>Mental toughness also plays an important role in sporting success. <a href="https://www.ncbi.nlm.nih.gov/pubmed/15773710">Mentally tough athletes</a> have an insatiable desire to succeed, have unshakable confidence, are highly motivated and adapt well to stressful situations. <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3737815/pdf/jssm-10-445.pdf">A study</a> of British athletes in 2011 found that those with low ratios were mentally tougher, more determined, more confident and more optimistic. </p>
<p>Physical fitness is an important determinant of success in many sports and athletic events. Favorable links between digit ratio and <a href="https://www.ncbi.nlm.nih.gov/pubmed/22141747">cardiorespiratory endurance</a> and muscular strength have been found in males. In <a href="https://www.ncbi.nlm.nih.gov/pubmed/28697407">a recent study</a> of Minnesotan high school boys, we found that those with lower ratios had better hand-grip strength (irrespective of age and body size) than their peers with higher ratios. Physical fitness is also an important indicator of good health, suggesting that people with low ratios are healthier.</p>
<p>The digit ratio is also assumed to be a good measure of adult steroid hormones because of its link with fetal steroid hormones. While there is little evidence to support this, men with low ratios do, however, experience more <a href="https://www.ncbi.nlm.nih.gov/pubmed/26025335">marked spikes in testosterone</a> during challenge situations, such as those experienced during competitive sport. Males with low digit ratios also tend to be <a href="https://www.ncbi.nlm.nih.gov/pubmed/26699684">more aggressive</a> and <a href="http://www.sciencedirect.com/science/article/pii/S0191886911001309">take more risks</a>.</p>
<p>The long and short of it? Sporting success is in your hands.</p><img src="https://counter.theconversation.com/content/82876/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>The authors do not work for, consult, own shares in or receive funding from any company or organization that would benefit from this article, and have disclosed no relevant affiliations beyond their academic appointment.</span></em></p>Athletic ability is often linked to size – of muscles and bones. New studies are suggesting, however, that the relative size of two fingers could be more predictive of ability.Grant Tomkinson, Professor, University of North DakotaMakailah Dyer, Graduate Student, University of North DakotaLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/813102017-08-25T01:24:34Z2017-08-25T01:24:34ZPostpartum depression can affect dads – and their hormones may be to blame<figure><img src="https://images.theconversation.com/files/182492/original/file-20170817-10986-dh8jpe.jpg?ixlib=rb-1.1.0&amp;q=45&amp;auto=format&amp;w=496&amp;fit=clip" /><figcaption><span class="caption">New fathers can feel low, too.</span> <span class="attribution"><a class="source" href="https://www.flickr.com/photos/lorix/6318744499">loriZ</a>, <a class="license" href="http://creativecommons.org/licenses/by-nc/4.0/">CC BY-NC</a></span></figcaption></figure><p>Postpartum depression has become more visible as celebrity moms including <a href="http://www.hachettebookgroup.com/titles/brooke-shields/down-came-the-rain/9781401308469/">Brooke Shields</a>, <a href="http://celebritybabies.people.com/2015/10/21/drew-barrymore-postpartum-depression-people-cover/">Drew Barrymore</a> and <a href="https://www.glamour.com/story/chrissy-teigen-postpartum-depression">Chrissy Teigen</a> have publicly shared their struggles with feeling sad and hopeless after birth. But when a father – Adam Busby, from reality TV show “OutDaughtered” – opened up about <a href="http://people.com/tv/outdaughtered-quintuplets-dad-adam-busby-suffering-postpartum-depression/">his own postpartum depression</a> in 2017, he <a href="http://www.intouchweekly.com/posts/adam-busby-depression-137710">received instant backlash</a>, including comments telling him to “man up.”</p>
<p>Despite the skepticism, postpartum depression in fathers is very real, with estimates that <a href="https://doi.org/10.1001/jama.2010.605">around 10 percent of men report symptoms</a> of depression following the birth of a child, about double the typical rate of depression in males. Postpartum depression <a href="https://doi.org/10.1146/annurev-clinpsy-101414-020426">in women has been linked with hormonal shifts</a>, but the role of hormones in men’s postpartum depression has been unknown.</p>
<p>In an attempt to solve this mystery, my colleagues and I recently tested whether men’s <a href="https://www.ncbi.nlm.nih.gov/pubmed/28757312">levels of the hormone testosterone are related to their postpartum depression risk</a> during early parenthood. We found that men’s testosterone levels might predict not only their own postpartum depression risk, but their partner’s depression risk as well. </p>
<h2>Testosterone levels in flux through life changes</h2>
<p><a href="https://en.wikipedia.org/wiki/Testosterone">Testosterone is an androgen hormone</a>, responsible for the development and maintenance of male secondary sex characteristics. It promotes muscle mass and body hair growth, and motivates sexual arousal and competitive behavior.</p>
<figure class="align-right zoomable">
<a href="https://images.theconversation.com/files/183037/original/file-20170822-1055-18mzeuu.jpg?ixlib=rb-1.1.0&amp;q=45&amp;auto=format&amp;w=1000&amp;fit=clip"><img alt="" src="https://images.theconversation.com/files/183037/original/file-20170822-1055-18mzeuu.jpg?ixlib=rb-1.1.0&amp;q=45&amp;auto=format&amp;w=237&amp;fit=clip" srcset="https://images.theconversation.com/files/183037/original/file-20170822-1055-18mzeuu.jpg?ixlib=rb-1.1.0&amp;q=45&amp;auto=format&amp;w=600&amp;h=728&amp;fit=crop&amp;dpr=1 600w, https://images.theconversation.com/files/183037/original/file-20170822-1055-18mzeuu.jpg?ixlib=rb-1.1.0&amp;q=30&amp;auto=format&amp;w=600&amp;h=728&amp;fit=crop&amp;dpr=2 1200w, https://images.theconversation.com/files/183037/original/file-20170822-1055-18mzeuu.jpg?ixlib=rb-1.1.0&amp;q=15&amp;auto=format&amp;w=600&amp;h=728&amp;fit=crop&amp;dpr=3 1800w, https://images.theconversation.com/files/183037/original/file-20170822-1055-18mzeuu.jpg?ixlib=rb-1.1.0&amp;q=45&amp;auto=format&amp;w=754&amp;h=915&amp;fit=crop&amp;dpr=1 754w, https://images.theconversation.com/files/183037/original/file-20170822-1055-18mzeuu.jpg?ixlib=rb-1.1.0&amp;q=30&amp;auto=format&amp;w=754&amp;h=915&amp;fit=crop&amp;dpr=2 1508w, https://images.theconversation.com/files/183037/original/file-20170822-1055-18mzeuu.jpg?ixlib=rb-1.1.0&amp;q=15&amp;auto=format&amp;w=754&amp;h=915&amp;fit=crop&amp;dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
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<span class="caption">Cotton top tamarin babies get care from both parents.</span>
<span class="attribution"><a class="source" href="https://www.flickr.com/photos/ekilby/26123804612">Eric Kilby</a>, <a class="license" href="http://creativecommons.org/licenses/by-sa/4.0/">CC BY-SA</a></span>
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<p>Many studies have found that testosterone dips in new fathers across the animal kingdom. Among animals that engage in the biparental care of offspring – Mongolian gerbils, Djungarian hamsters, California mice and cotton-top tamarins – males show <a href="https://doi.org/10.1111/jne.12176">lower testosterone levels following the birth of pups</a>.</p>
<p>Human males also often show declines in testosterone around the birth of their infants. In one of the <a href="https://doi.org/10.1073/pnas.1105403108">largest studies of testosterone and fatherhood</a>, <a href="http://anthropology.nd.edu/faculty-and-staff/faculty-by-alpha/lee-gettler/">anthropologist Lee Gettler</a> and his colleagues followed over 600 single men in the Philippines for about five years. If men became partnered fathers during that time, their testosterone levels decreased more than the men who stayed single. Gettler also found that fathers who spent more time with their children showed lower testosterone, suggesting that testosterone may be suppressed by paternal caregiving. </p>
<p>Along similar lines, <a href="http://edelsteinlab.psych.lsa.umich.edu/">psychologist Robin Edelstein</a> and I found that men assessed repeatedly over their partner’s pregnancy showed <a href="https://doi.org/10.1016/j.yhbeh.2016.07.005">declining testosterone levels from early to late pregnancy</a>. Men whose testosterone dropped more dramatically were more likely to report postpartum commitment and investment in their romantic relationships with their partners.</p>
<p>Researchers still haven’t identified exactly what causes men’s testosterone to change over the transition to parenthood. Possible suspects include proximity to the partner or infant, increased stress or disrupted sleep and exercise routines.</p>
<h2>Lower testosterone, higher depression</h2>
<p>Previous research has <a href="https://doi.org/10.1210/jcem.84.2.5495">linked testosterone with men’s depression levels</a> in general. Low testosterone may contribute to the feelings of lethargy and disinterest in normally pleasurable activities that characterize depression. In fact, some psychiatrists have even suggested prescribing <a href="https://doi.org/10.1176/appi.ajp.160.1.105">testosterone supplements to treat depression in men</a>. However, no studies had specifically looked at the potential role of testosterone in fathers’ postpartum depression.</p>
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<a href="https://images.theconversation.com/files/183201/original/file-20170823-6594-vm7cf3.jpg?ixlib=rb-1.1.0&amp;q=45&amp;auto=format&amp;w=1000&amp;fit=clip"><img alt="" src="https://images.theconversation.com/files/183201/original/file-20170823-6594-vm7cf3.jpg?ixlib=rb-1.1.0&amp;q=45&amp;auto=format&amp;w=754&amp;fit=clip" srcset="https://images.theconversation.com/files/183201/original/file-20170823-6594-vm7cf3.jpg?ixlib=rb-1.1.0&amp;q=45&amp;auto=format&amp;w=600&amp;h=400&amp;fit=crop&amp;dpr=1 600w, https://images.theconversation.com/files/183201/original/file-20170823-6594-vm7cf3.jpg?ixlib=rb-1.1.0&amp;q=30&amp;auto=format&amp;w=600&amp;h=400&amp;fit=crop&amp;dpr=2 1200w, https://images.theconversation.com/files/183201/original/file-20170823-6594-vm7cf3.jpg?ixlib=rb-1.1.0&amp;q=15&amp;auto=format&amp;w=600&amp;h=400&amp;fit=crop&amp;dpr=3 1800w, https://images.theconversation.com/files/183201/original/file-20170823-6594-vm7cf3.jpg?ixlib=rb-1.1.0&amp;q=45&amp;auto=format&amp;w=754&amp;h=503&amp;fit=crop&amp;dpr=1 754w, https://images.theconversation.com/files/183201/original/file-20170823-6594-vm7cf3.jpg?ixlib=rb-1.1.0&amp;q=30&amp;auto=format&amp;w=754&amp;h=503&amp;fit=crop&amp;dpr=2 1508w, https://images.theconversation.com/files/183201/original/file-20170823-6594-vm7cf3.jpg?ixlib=rb-1.1.0&amp;q=15&amp;auto=format&amp;w=754&amp;h=503&amp;fit=crop&amp;dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
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<span class="caption">How does the birth of a baby affect a father’s testosterone and his mental health?</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/tired-daddy-naughty-baby-boy-asian-193271417">szefei/Shutterstock.com</a></span>
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<p>My colleagues and I analyzed data from the <a href="https://www.nichd.nih.gov/research/supported/Pages/cchn.aspx">Community Child Health Research Network</a>, a National Institutes of Health-funded study of new parents’ health and well-being. The study recruited moms after the birth of an infant and followed them for several years, along with their partners. At one of the study sites, in Lake County, Illinois, men also provided saliva samples for testosterone analysis when their infants were around nine months old. Both moms and dads reported on their symptoms of depression several times across the first few years of parenthood.</p>
<p>We found that dads with lower testosterone reported feeling more depressed. This fits with other research into how testosterone and depression work together. But ours is the first study to observe this relationship specifically in fathers of infants. Given that many men show drops in testosterone over the transition to parenthood, this finding may help explain why the postpartum period is such a high-risk time for depression in men.</p>
<h2>An unexpected side effect – for the moms</h2>
<p>We were surprised when we examined links between men’s testosterone and their partners’ depression. Yes, low testosterone seemed to put men at higher risk for depressive symptoms. But men’s levels had the opposite effect for their partners: Women with lower-testosterone partners actually reported fewer symptoms of depression. Why would that be?</p>
<p>We tested one possible explanation by looking at how women rated their relationships. It turned out that moms paired with low-testosterone men reported higher relationship satisfaction, and their higher relationship satisfaction predicted lower rates of depressive symptoms.</p>
<p>In other words, having a low-testosterone mate might make for a better-quality relationship, in turn reducing the likelihood that women will become depressed. We know <a href="http://dx.doi.org/10.1037/0022-3514.65.6.1243">social support from a partner</a> can protect women against developing postpartum depression, so our finding fits with that research. Lower-testosterone men may be <a href="https://doi.org/10.1016/j.yhbeh.2016.07.005">more dedicated to their relationships</a> or <a href="https://doi.org/10.1073/pnas.1105403108">spend more time with children</a>, helping to relieve some of the pressure on moms. </p>
<p>At around 15 months postpartum, we also checked moms’ ratings of whether their partners hurt, threatened, yelled at or insulted them. If men had higher testosterone, moms reported higher levels of intimate partner aggression about six months later. Testosterone is associated with <a href="https://doi.org/10.1016/j.neubiorev.2004.12.007">more aggressive and competitive behavior</a>. Our finding shows a potential dark side to high testosterone in the postpartum period.</p>
<p>Dads also told us about their parenting stress at 15 months postpartum, reporting on emotions such as feeling trapped by parenting responsibilities, believing their children made too many demands on them and lacking warm feelings toward their children. At first, we didn’t find a link between men’s testosterone levels and their parenting stress. But after we statistically controlled for the relationship between low testosterone and depression, we saw that higher testosterone put men at greater risk of experiencing problems in the parenting relationship. This result suggests that, once you adjust for their potentially lower risk of depression, high-testosterone men may find parenting to be more stressful.</p>
<h2>A happy medium for testosterone?</h2>
<p><a href="https://www.ncbi.nlm.nih.gov/pubmed/28757312">Our results suggest</a> that fathers of infants might be at risk at both sides of the postpartum testosterone spectrum. At low levels, they might be more vulnerable to depression. But at high levels, they might have less satisfying and more aggressive relationships, less happy partners and more parenting stress. In terms of resilience to depression and stress, men with average levels of postpartum testosterone seemed to fare best.</p>
<p>Our findings reveal that men’s postpartum testosterone has a complex relationship with family health. From an evolutionary perspective, lower testosterone during the transition to parenthood may help motivate men to invest in their family. In the animal kingdom, lower-testosterone males <a href="https://doi.org/10.1111/jne.12176">spend more time with infant pups</a> and show less aggression toward them. So it makes sense that human males would show shifts in testosterone as they adapt to parenthood.</p>
<p>But these shifts may make men more vulnerable to mood disorder symptoms. Perhaps this is because lower-testosterone men are taking a more hands-on role in the family and helping more with infant care. Their contributions are great news from the family’s perspective, but may put men at heightened risk of some of the same depressive symptoms that <a href="http://www.salon.com/2013/02/25/is_motherhood_causing_my_depression/">many new mothers face</a>. </p>
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<a href="https://images.theconversation.com/files/183030/original/file-20170822-30494-12wv57l.jpg?ixlib=rb-1.1.0&amp;q=45&amp;auto=format&amp;w=1000&amp;fit=clip"><img alt="" src="https://images.theconversation.com/files/183030/original/file-20170822-30494-12wv57l.jpg?ixlib=rb-1.1.0&amp;q=45&amp;auto=format&amp;w=754&amp;fit=clip" srcset="https://images.theconversation.com/files/183030/original/file-20170822-30494-12wv57l.jpg?ixlib=rb-1.1.0&amp;q=45&amp;auto=format&amp;w=600&amp;h=400&amp;fit=crop&amp;dpr=1 600w, https://images.theconversation.com/files/183030/original/file-20170822-30494-12wv57l.jpg?ixlib=rb-1.1.0&amp;q=30&amp;auto=format&amp;w=600&amp;h=400&amp;fit=crop&amp;dpr=2 1200w, https://images.theconversation.com/files/183030/original/file-20170822-30494-12wv57l.jpg?ixlib=rb-1.1.0&amp;q=15&amp;auto=format&amp;w=600&amp;h=400&amp;fit=crop&amp;dpr=3 1800w, https://images.theconversation.com/files/183030/original/file-20170822-30494-12wv57l.jpg?ixlib=rb-1.1.0&amp;q=45&amp;auto=format&amp;w=754&amp;h=503&amp;fit=crop&amp;dpr=1 754w, https://images.theconversation.com/files/183030/original/file-20170822-30494-12wv57l.jpg?ixlib=rb-1.1.0&amp;q=30&amp;auto=format&amp;w=754&amp;h=503&amp;fit=crop&amp;dpr=2 1508w, https://images.theconversation.com/files/183030/original/file-20170822-30494-12wv57l.jpg?ixlib=rb-1.1.0&amp;q=15&amp;auto=format&amp;w=754&amp;h=503&amp;fit=crop&amp;dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
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<span class="caption">New parenthood is hard, whether you’re a man or a woman.</span>
<span class="attribution"><a class="source" href="https://www.flickr.com/photos/nataliebroach/3478461504">Natalie Broach</a>, <a class="license" href="http://creativecommons.org/licenses/by-nc-nd/4.0/">CC BY-NC-ND</a></span>
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<p>After all, caring for infants is hard, draining work. In modern industrialized societies like the United States, many new parents lack the extended family support networks that can help lighten the burden of childcare. And in the U.S., <a href="http://www.slate.com/blogs/xx_factor/2017/06/15/most_major_u_s_employers_fail_on_paid_paternity_leave_the_aclu_says_that.html">paternity leave is a rarity</a>, and many dads struggle with family-unfriendly work arrangements that drain time and energy. Just as new moms can feel overwhelmed and isolated after spending long hours tending to their babies, so too can dads.</p>
<p>If new dads (or moms) are experiencing depressed moods after the birth of their infants, they can take some comfort in the fact that these feelings are normal – and may even be rooted in our evolutionary biology. There’s <a href="http://postpartummen.com">no shame in seeking help</a>, whether it’s talking to a friend, prioritizing sleep and exercise, or visiting a therapist. <a href="http://www.parents.com/parenting/dads/sad-dads/">Postpartum depression affects the whole family</a> and should be taken seriously.</p><img src="https://counter.theconversation.com/content/81310/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Darby Saxbe receives funding from the National Science Foundation. </span></em></p>Having a newborn can be rough, whether you're a mom or a dad. New research ties men's testosterone to their postpartum depression – with some surprising upsides for their partners.Darby Saxbe, Assistant Professor of Psychology, University of Southern California – Dornsife College of Letters, Arts and SciencesLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/824792017-08-16T01:36:12Z2017-08-16T01:36:12ZDoes biology explain why men outnumber women in tech?<figure><img src="https://images.theconversation.com/files/182132/original/file-20170815-6110-1og4pid.jpg?ixlib=rb-1.1.0&amp;rect=151%2C43%2C2897%2C2140&amp;q=45&amp;auto=format&amp;w=496&amp;fit=clip" /><figcaption><span class="caption">Who&#39;s missing from this picture?</span> <span class="attribution"><a class="source" href="https://www.flickr.com/photos/lws/3263880963">Lawrence Sinclair</a>, <a class="license" href="http://creativecommons.org/licenses/by-nc-nd/4.0/">CC BY-NC-ND</a></span></figcaption></figure><p>It’s no secret that <a href="https://techcrunch.com/tag/diversity-report/">Silicon Valley employs</a> many <a href="http://money.cnn.com/interactive/technology/tech-diversity-data/">more men than women</a> <a href="https://www.eeoc.gov/eeoc/statistics/reports/hightech/">in tech jobs</a>. What’s much harder to agree on is why.</p>
<p>The recent <a href="https://motherboard.vice.com/en_us/article/evzjww/here-are-the-citations-for-the-anti-diversity-manifesto-circulating-at-google">anti-diversity memo</a> by a now former Google engineer has pushed this topic into the spotlight. The writer argued there are ways to explain the gender gap in tech that don’t rely on bias and discrimination – specifically, biological sex differences. Setting aside how this assertion would affect questions about how to move toward greater equity in tech fields, how well does his wrap-up represent what researchers know about the science of sex and gender?</p>
<p>As a social scientist who’s been conducting psychological research about sex and gender for almost 50 years, I agree that biological differences between the sexes likely are part of the reason we see fewer women than men in the ranks of Silicon Valley’s tech workers. But the road between biology and employment is long and bumpy, and any causal connection does not rule out the relevance of nonbiological causes. Here’s what the research actually says.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/182138/original/file-20170815-21358-10smx34.jpg?ixlib=rb-1.1.0&amp;q=45&amp;auto=format&amp;w=1000&amp;fit=clip"><img alt="" src="https://images.theconversation.com/files/182138/original/file-20170815-21358-10smx34.jpg?ixlib=rb-1.1.0&amp;q=45&amp;auto=format&amp;w=754&amp;fit=clip" srcset="https://images.theconversation.com/files/182138/original/file-20170815-21358-10smx34.jpg?ixlib=rb-1.1.0&amp;q=45&amp;auto=format&amp;w=600&amp;h=450&amp;fit=crop&amp;dpr=1 600w, https://images.theconversation.com/files/182138/original/file-20170815-21358-10smx34.jpg?ixlib=rb-1.1.0&amp;q=30&amp;auto=format&amp;w=600&amp;h=450&amp;fit=crop&amp;dpr=2 1200w, https://images.theconversation.com/files/182138/original/file-20170815-21358-10smx34.jpg?ixlib=rb-1.1.0&amp;q=15&amp;auto=format&amp;w=600&amp;h=450&amp;fit=crop&amp;dpr=3 1800w, https://images.theconversation.com/files/182138/original/file-20170815-21358-10smx34.jpg?ixlib=rb-1.1.0&amp;q=45&amp;auto=format&amp;w=754&amp;h=566&amp;fit=crop&amp;dpr=1 754w, https://images.theconversation.com/files/182138/original/file-20170815-21358-10smx34.jpg?ixlib=rb-1.1.0&amp;q=30&amp;auto=format&amp;w=754&amp;h=566&amp;fit=crop&amp;dpr=2 1508w, https://images.theconversation.com/files/182138/original/file-20170815-21358-10smx34.jpg?ixlib=rb-1.1.0&amp;q=15&amp;auto=format&amp;w=754&amp;h=566&amp;fit=crop&amp;dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Is she a computer natural?</span>
<span class="attribution"><a class="source" href="https://www.flickr.com/photos/zorgnetwerknederland/9423176668">Micah Sittig</a>, <a class="license" href="http://creativecommons.org/licenses/by/4.0/">CC BY</a></span>
</figcaption>
</figure>
<h2>Are girls just born less suited for tech?</h2>
<p>There is no direct causal evidence that biology causes the lack of women in tech jobs. But many, if not most, psychologists do give credence to the general idea that prenatal and early postnatal <a href="https://doi.org/10.1002/jnr.23832">exposure to hormones</a> such as testosterone and other androgens <a href="https://doi.org/10.1186/s13293-015-0022-1">affect human psychology</a>. In humans, testosterone is ordinarily elevated in males from about weeks eight to 24 of gestation and also during early postnatal development. </p>
<p>Ethical restraints obviously preclude experimenting on human fetuses and babies to understand the effects of this greater exposure of males to testosterone. Instead, researchers have studied individuals exposed to hormonal environments that are <a href="https://doi.org/10.1023/A:1022492106974">abnormal</a> because of <a href="https://doi.org/10.1016/j.yhbeh.2007.05.015">unusual genetic conditions</a> or hormonally active drugs <a href="https://doi.org/10.1007/s10508-016-0923-z">prescribed to pregnant women</a>. Such studies have suggested that early androgen exposure does have masculinizing effects on girls’ juvenile play preferences and behavior, aggression, sexual orientation and gender identity and <a href="https://doi.org/10.1016/j.psyneuen.2015.01.022">possibly on spatial ability</a> and responsiveness to cues that <a href="https://doi.org/10.1098/rstb.2015.0125">certain behaviors are culturally female-appropriate</a>.</p>
<p>Early hormonal exposure is only one part of a complex of biological processes that <a href="https://doi.org/10.1002/jnr.23884">contribute to sexual differentiation</a>. Driven by both direct and roundabout messages from the X and Y chromosomes, the effects of these processes on human psychology are largely unknown, given the early stage of the relevant science.</p>
<p>Other studies inform the nature-nurture question by comparing the behaviors of boys and girls who are so young that socialization has not exerted its full influence.</p>
<p><a href="https://doi.org/10.1037/0033-2909.132.1.33">Early sex differences emerge mainly</a> on <a href="https://doi.org/10.1111/j.1750-8606.2012.00254.x">broad dimensions of temperament</a>. One such dimension is what psychologists call “surgency”; it’s greater in boys and manifests in motor activity, impulsivity and experiencing pleasure from high-intensity activities. The other dimension is in what we term “effortful control”; it’s greater in girls and emerges in the self-regulatory skills of greater attention span, ability to focus and shift attention and inhibitory control. This aspect of temperament also includes greater perceptual sensitivity and experience of pleasure from low-intensity activities.</p>
<p>This research on temperament does suggest that nature instills some psychological sex differences. But scientists don’t fully understand the pathways from these aspects of child temperament to adult personality and abilities.</p>
<h2>Is there a gender divide on tech-relevant traits?</h2>
<p>Another approach to the women-in-tech question involves comparing the sexes on traits thought most relevant to participation in tech. In this case, it doesn’t matter whether these traits follow from nature or nurture. The usual suspects include mathematical and spatial abilities.</p>
<p>The sex difference in average mathematical ability that <a href="https://doi.org/10.1002/j.2333-8504.1971.tb00807.x">once favored males</a> has <a href="https://doi.org/10.1126/science.1160364">disappeared in the general U.S. population</a>. There is also a <a href="https://doi.org/10.1016/j.intell.2016.09.003">decline in the preponderance of males</a> among the very top scorers on demanding math tests. Yet, males tend to score <a href="https://doi.org/10.1016/j.tics.2013.10.011">higher on most tests of spatial abilities</a>, especially tests of <a href="https://doi.org/10.1007/s10648-012-9215-x">mentally rotating three-dimensional objects</a>, and these skills appear to be <a href="http://dx.doi.org/10.1037/a0016127">helpful in STEM fields</a>.</p>
<p>Of course people choose occupations based on their interests as well as their abilities. So the robust and large sex difference on measures of people-oriented versus thing-oriented interests deserves consideration.</p>
<p><a href="https://dx.doi.org/10.1037/a0017364">Research shows that</a>, in general, women are more interested in people compared with men, who are more interested in things. To the extent that tech occupations are concerned more with things than people, men would on average <a href="https://doi.org/10.1016/j.jvb.2015.09.007">be more attracted to them</a>. For example, positions such as computer systems engineer and network and database architect require extensive knowledge of electronics, mathematics, engineering principles and telecommunication systems. Success in such work is not as dependent on qualities such as social sensitivity and emotional intelligence as are positions in, for instance, early childhood education and retail sales.</p>
<p>Women and men also differ in their life goals, with women placing a higher priority than men on <a href="https://doi.org/10.1177/1088868316642141">working with and helping people</a>. Jobs in STEM are in general not viewed as providing much opportunity to satisfy these life goals. But technology does offer specializations that prioritize social and community goals (such as designing healthcare systems) or reward social skills (for instance, optimizing the interaction of people with machines and information). Such positions may, on average, be <a href="https://dx.doi.org/10.1037/a0025199">relatively appealing to women</a>. More generally, women’s overall <a href="https://doi.org/10.1371/journal.pone.0057988">superiority on reading</a> <a href="http://dx.doi.org/10.1080/00221325.2015.1036833">and writing</a> as well as <a href="https://dx.doi.org/10.1017/CBO9780511628191.006">social skills</a> <a href="http://dx.doi.org/10.1037/a0017286">would advantage them</a> in many occupations.</p>
<p>Virtually all sex differences consist of overlapping distributions of women and men. For example, despite the quite large sex difference in average height, some women are taller than most men and some men are shorter than most women. Although psychological sex differences are statistically smaller than this height difference, some of the differences most relevant to tech are substantial, particularly interest in people versus things and spatial ability in mental rotations. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/182136/original/file-20170815-26751-uke216.jpg?ixlib=rb-1.1.0&amp;q=45&amp;auto=format&amp;w=1000&amp;fit=clip"><img alt="" src="https://images.theconversation.com/files/182136/original/file-20170815-26751-uke216.jpg?ixlib=rb-1.1.0&amp;q=45&amp;auto=format&amp;w=754&amp;fit=clip" srcset="https://images.theconversation.com/files/182136/original/file-20170815-26751-uke216.jpg?ixlib=rb-1.1.0&amp;q=45&amp;auto=format&amp;w=600&amp;h=450&amp;fit=crop&amp;dpr=1 600w, https://images.theconversation.com/files/182136/original/file-20170815-26751-uke216.jpg?ixlib=rb-1.1.0&amp;q=30&amp;auto=format&amp;w=600&amp;h=450&amp;fit=crop&amp;dpr=2 1200w, https://images.theconversation.com/files/182136/original/file-20170815-26751-uke216.jpg?ixlib=rb-1.1.0&amp;q=15&amp;auto=format&amp;w=600&amp;h=450&amp;fit=crop&amp;dpr=3 1800w, https://images.theconversation.com/files/182136/original/file-20170815-26751-uke216.jpg?ixlib=rb-1.1.0&amp;q=45&amp;auto=format&amp;w=754&amp;h=566&amp;fit=crop&amp;dpr=1 754w, https://images.theconversation.com/files/182136/original/file-20170815-26751-uke216.jpg?ixlib=rb-1.1.0&amp;q=30&amp;auto=format&amp;w=754&amp;h=566&amp;fit=crop&amp;dpr=2 1508w, https://images.theconversation.com/files/182136/original/file-20170815-26751-uke216.jpg?ixlib=rb-1.1.0&amp;q=15&amp;auto=format&amp;w=754&amp;h=566&amp;fit=crop&amp;dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Silicon Valley has been faulted for its ‘brogrammer’ culture, which can be unwelcoming to women.</span>
<span class="attribution"><a class="source" href="https://www.flickr.com/photos/zorgnetwerknederland/9423176668">Zorgnetwerk Nederland</a>, <a class="license" href="http://creativecommons.org/licenses/by-nc-nd/4.0/">CC BY-NC-ND</a></span>
</figcaption>
</figure>
<h2>If not biology, then what are the causes?</h2>
<p>Given the absence of clear-cut evidence that tech-relevant abilities and interests flow mainly from biology, there’s plenty of room to consider socialization and gender stereotyping.</p>
<p>Because humans are born undeveloped, parents and others provide extensive socialization, generally intended to promote personality traits and skills they think will help offspring in their future adult roles. To the extent that women and men have different adult lives, caregivers tend to <a href="https://dx.doi.org/10.1037/0033-2909.109.2.267">promote sex-typical activities and interests</a> in children – dolls for girls, toy trucks for boys. Conventional socialization can <a href="https://doi.org/10.1111/cdev.12569">set children on the route</a> to conventional career choices.</p>
<p>Even <a href="https://doi.org/10.1068/p3331">very young children</a> form <a href="https://doi.org/10.1016/0163-6383(94)90037-X">gender stereotypes</a> as <a href="https://dx.doi.org/10.1037/a0037215">they observe women and men</a> enacting their society’s division of labor. They <a href="http://www.jstor.org/stable/1128709">automatically learn about gender</a> from what they see adults doing in the home and at work. Eventually, to explain the differences they see in what men and women do and how they do it, children draw the conclusion that the sexes to some extent have different underlying traits. Divided labor thus conveys the message that <a href="https://doi.org/10.1006/drev.1993.1007">males and females have different attributes</a>.</p>
<p>These <a href="https://doi.org/10.1111/1471-6402.t01-1-00066">gender stereotypes usually include</a> beliefs that women excel in qualities such as warmth and concern for others, which psychologists label as communal. Stereotypes also suggest men have higher levels of qualities such as assertiveness and dominance, which psychologists label as agentic. <a href="https://doi.org/10.1177/0146167200262001">These stereotypes are shared</a> in cultures and shape individuals’ <a href="https://doi.org/10.1016/B978-0-12-394281-4.00002-7">gender identities as well as societal norms</a> about appropriate female and male behaviors.</p>
<p>Gender stereotypes set the stage for prejudice and discrimination directed toward those who deviate from gender norms. If, for example, people accept the stereotype that women are warm and emotional but not tough and rational, <a href="https://doi.org/10.1093/oxfordhb/9780199363643.013.7">gatekeepers may close out women</a> from many engineering and tech jobs, even those women who are atypical of their sex. In addition, women talented in tech may falter if they themselves <a href="https://doi.org/10.1002/j.2161-0045.2014.00075.x">internalize societal stereotypes</a> about <a href="https://doi.org/10.1007/s11162-015-9375-x">women’s inferiority in tech-relevant attributes</a>. Also, women’s <a href="http://dx.doi.org/10.1037/a0012702">anxiety that they may confirm</a> these negative stereotypes can <a href="https://doi.org/10.4135/9781446269930.n26">lower their actual performance</a>.</p>
<p>It’s therefore not surprising that research provides <a href="https://books.google.com/books?hl=en&amp;lr=&amp;id=xPCQM6g7CQ0C&amp;oi=fnd&amp;pg=PA1&amp;ots=XKHVbPVdIO&amp;sig=L2ZncU0XyBEph7ujaLq4usXSmTY#v=onepage&amp;q&amp;f=false">evidence that women generally</a> have to <a href="https://dx.doi.org/10.1037/a0036734">meet a higher standard</a> to attain jobs and recognition in fields that are culturally masculine and dominated by men. However, there is some recent evidence of <a href="https://doi.org/10.17226/12062">preferential hiring of women in STEM</a> at U.S. research-intensive institutions. Qualified women who apply for such positions have a better chance of being interviewed and receiving offers than do male job candidates. <a href="https://theconversation.com/women-preferred-for-stem-professorships-as-long-as-theyre-equal-to-or-better-than-male-candidates-49411">Experimental simulation of hiring</a> of STEM faculty yielded similar findings.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/182140/original/file-20170815-28398-au0sfi.jpg?ixlib=rb-1.1.0&amp;q=45&amp;auto=format&amp;w=1000&amp;fit=clip"><img alt="" src="https://images.theconversation.com/files/182140/original/file-20170815-28398-au0sfi.jpg?ixlib=rb-1.1.0&amp;q=45&amp;auto=format&amp;w=754&amp;fit=clip" srcset="https://images.theconversation.com/files/182140/original/file-20170815-28398-au0sfi.jpg?ixlib=rb-1.1.0&amp;q=45&amp;auto=format&amp;w=600&amp;h=450&amp;fit=crop&amp;dpr=1 600w, https://images.theconversation.com/files/182140/original/file-20170815-28398-au0sfi.jpg?ixlib=rb-1.1.0&amp;q=30&amp;auto=format&amp;w=600&amp;h=450&amp;fit=crop&amp;dpr=2 1200w, https://images.theconversation.com/files/182140/original/file-20170815-28398-au0sfi.jpg?ixlib=rb-1.1.0&amp;q=15&amp;auto=format&amp;w=600&amp;h=450&amp;fit=crop&amp;dpr=3 1800w, https://images.theconversation.com/files/182140/original/file-20170815-28398-au0sfi.jpg?ixlib=rb-1.1.0&amp;q=45&amp;auto=format&amp;w=754&amp;h=566&amp;fit=crop&amp;dpr=1 754w, https://images.theconversation.com/files/182140/original/file-20170815-28398-au0sfi.jpg?ixlib=rb-1.1.0&amp;q=30&amp;auto=format&amp;w=754&amp;h=566&amp;fit=crop&amp;dpr=2 1508w, https://images.theconversation.com/files/182140/original/file-20170815-28398-au0sfi.jpg?ixlib=rb-1.1.0&amp;q=15&amp;auto=format&amp;w=754&amp;h=566&amp;fit=crop&amp;dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Any career depends on training and education that build on innate interest and talent.</span>
<span class="attribution"><a class="source" href="https://www.flickr.com/photos/24929786@N02/2367468669">Todd Ludwig</a>, <a class="license" href="http://creativecommons.org/licenses/by-nc-sa/4.0/">CC BY-NC-SA</a></span>
</figcaption>
</figure>
<h2>Why not both nature and nurture?</h2>
<p>Many pundits make the mistake of assuming that scientific evidence favoring sociocultural causes for the dearth of women in tech invalidates biological causes, or vice versa. These assumptions are far too simplistic because most complex human behaviors reflect some mix of nature and nurture. </p>
<p>And the discourse is further compromised as the <a href="https://www.nytimes.com/2017/08/08/technology/the-culture-wars-have-come-to-silicon-valley.html?_r=0">debate becomes</a> <a href="https://www.washingtonpost.com/opinions/the-google-memo-isnt-the-interesting-part-of-the-story/2017/08/11/de3f8876-7ecb-11e7-9d08-b79f191668ed_story.html">more politicized</a>. Arguing for sociocultural causes seems the more progressive and politically correct stance today. Arguing for biological causes seems the more conservative and reactionary position. Fighting ideological wars distracts from figuring out what <a href="https://doi.org/10.1177/2372732214549471">changes in organizational practices and cultures</a> would <a href="https://www.nytimes.com/2017/08/15/opinion/silicon-valley-women-hiring-diversity.html">foster the inclusion of women in tech</a> and in the scientific workforce in general.</p>
<p>Politicizing such debates threatens scientific progress and doesn’t help unravel what a fair and diverse organization is and how to create one. Unfortunately, well-meaning efforts of organizations to <a href="https://theconversation.com/tech-companies-spend-big-money-on-bias-training-but-it-hasnt-improved-diversity-numbers-44411">promote diversity and inclusion</a> can be ineffective, often because they are too <a href="https://doi.org/10.1177/0003122415596416">coercive and restrictive of managers’ autonomy</a>. The outrage in James Damore’s manifesto suggests that Google might want to take a close look at its diversity initiatives.</p>
<p>At any rate, neither nature-oriented nor nurture-oriented science can fully account for the underrepresentation of women in tech jobs. A coherent and open-minded stance acknowledges the possibility of both biological and social influences on career interests and competencies.</p>
<p>Regardless of whether nature or nurture is more powerful for explaining the lack of women in tech careers, people should guard against acting on the assumption of a gender binary. It makes more sense to treat individuals of both sexes as located somewhere on a continuum of masculine and feminine interests and abilities. Treating people as individuals rather than merely stereotyping them as male or female is difficult, given how quickly our automatic stereotypes kick in. But working toward this goal would foster equity and diversity in tech and other sectors of the economy.</p><img src="https://counter.theconversation.com/content/82479/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Alice H. Eagly does not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>Here's what research actually says about differences between males and females – and the question of what's innate and what's acquired.Alice H. Eagly, Professor of Psychology; Faculty Fellow Institute for Policy Research; Professor of Management and Organizations, Northwestern UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/782082017-05-24T15:24:02Z2017-05-24T15:24:02ZDrug-resistant cancers kill millions – here's how we're tackling them<figure><img src="https://images.theconversation.com/files/170600/original/file-20170523-5786-k70dxd.jpg?ixlib=rb-1.1.0&amp;q=45&amp;auto=format&amp;w=496&amp;fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><a class="source" href="https://www.shutterstock.com/image-illustration/prostate-cancer-cells-sem-202719580?src=Zx2Z6E5-6ss2iWk66US-lA-1-47">royalstockphoto.com</a></span></figcaption></figure><p>Cancer treatment is often highly effective at first, yet patients’ tumours <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4914245/">sometimes</a> stop responding – even to the most advanced therapies. Or in cases where the patient has gone into remission and the cancer has apparently been thwarted, it returns and no longer responds to treatment. In both cases, this is because the cancer cells evolve. </p>
<p>Most of us are familiar with <a href="https://theconversation.com/explainer-theory-of-evolution-2276">Darwinian evolution</a>, whereby individual traits that are advantageous in an environment tend to survive to become dominant features in a species. In the 1970s, the American cancer researcher <a href="https://www.washingtonpost.com/national/health-science/peter-nowell-who-has-died-at-88-revolutionized-cancer-research--by-accident/2017/01/12/c1a92056-d8d5-11e6-9f9f-5cdb4b7f8dd7_story.html">Peter Nowell</a> established <a href="https://www.ncbi.nlm.nih.gov/pubmed/959840?dopt=Abstract&amp;holding=npg">that</a> a similar thing happens with cancer. </p>
<p>Trying to overcome this problem is one of the key frontiers in 21st century cancer research. The good news is that the progress looks promising. </p>
<h2>How cancers evolve</h2>
<p>Cancers often arise because the <a href="https://www.cancer.gov/about-cancer/causes-prevention/genetics/brca-fact-sheet#q1">genes responsible</a> for repairing DNA, <a href="https://ghr.nlm.nih.gov/gene/TP53">and the genes</a> that kill off cells with badly damaged DNA, become damaged. This creates an environment where cancerous mutations in DNA are not repaired or removed and are allowed to accumulate. Not only does this allow tumours to grow in the first place, it also means they are more able to adapt and evolve to become drug-resistant – creating a <a href="https://blogs.scientificamerican.com/guest-blog/the-hallmarks-of-cancer-7-genome-instability-and-mutation/">vicious circle</a>. </p>
<p>Treatments themselves can also act as a selective pressure that drives cancer cells to evolve. To take an example from prostate cancer, which is my research area, tumours are very responsive to being <a href="https://www.cancer.org/cancer/prostate-cancer/treating/hormone-therapy.html">deprived of testosterone</a> since they usually depend on the hormone to grow in their early stages. In some cases, however, the disease becomes resistant to this treatment. </p>
<p>Normally, the body needs testosterone to activate the <a href="https://ghr.nlm.nih.gov/gene/AR">receptors</a> responsible for switching on genes that direct male sexual characteristics and certain other traits, including the growth of the prostate tissue. But where, for example, there are mutations to the gene that encodes this receptor, it can enable the receptor to be activated by other molecules. </p>
<p>In such circumstances, lowering a patient’s testosterone level will no longer act as a block on the growth of the cancer cells. This is known as castrate-resistant prostate cancer. Where it has spread to produce secondary tumours (metastasis), this highly aggressive form of the disease is considered incurable.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/170795/original/file-20170524-31362-1wv3fig.jpg?ixlib=rb-1.1.0&amp;q=45&amp;auto=format&amp;w=1000&amp;fit=clip"><img alt="" src="https://images.theconversation.com/files/170795/original/file-20170524-31362-1wv3fig.jpg?ixlib=rb-1.1.0&amp;q=45&amp;auto=format&amp;w=754&amp;fit=clip" srcset="https://images.theconversation.com/files/170795/original/file-20170524-31362-1wv3fig.jpg?ixlib=rb-1.1.0&amp;q=45&amp;auto=format&amp;w=600&amp;h=400&amp;fit=crop&amp;dpr=1 600w, https://images.theconversation.com/files/170795/original/file-20170524-31362-1wv3fig.jpg?ixlib=rb-1.1.0&amp;q=30&amp;auto=format&amp;w=600&amp;h=400&amp;fit=crop&amp;dpr=2 1200w, https://images.theconversation.com/files/170795/original/file-20170524-31362-1wv3fig.jpg?ixlib=rb-1.1.0&amp;q=15&amp;auto=format&amp;w=600&amp;h=400&amp;fit=crop&amp;dpr=3 1800w, https://images.theconversation.com/files/170795/original/file-20170524-31362-1wv3fig.jpg?ixlib=rb-1.1.0&amp;q=45&amp;auto=format&amp;w=754&amp;h=503&amp;fit=crop&amp;dpr=1 754w, https://images.theconversation.com/files/170795/original/file-20170524-31362-1wv3fig.jpg?ixlib=rb-1.1.0&amp;q=30&amp;auto=format&amp;w=754&amp;h=503&amp;fit=crop&amp;dpr=2 1508w, https://images.theconversation.com/files/170795/original/file-20170524-31362-1wv3fig.jpg?ixlib=rb-1.1.0&amp;q=15&amp;auto=format&amp;w=754&amp;h=503&amp;fit=crop&amp;dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">The verdict.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/man-consultation-dialogue-181677431?src=Zx2Z6E5-6ss2iWk66US-lA-1-60">Image Point Fr</a></span>
</figcaption>
</figure>
<p>Resistance mechanisms have also been well documented in response to radiotherapy and chemotherapy. In chemotherapy, for example, drug resistance is <a href="https://www.ncbi.nlm.nih.gov/pubmed/15641020?dopt=Abstract&amp;holding=npg">said to be</a> responsible for 90% of treatment failures where there are secondary tumours. </p>
<p>A particularly interesting resistance mechanism is one where in response to certain treatments, cancer cells actually change their cell type from those which make up the majority of most organs (epithelial), to cells more involved in hormonal and nerve signaling (neuroendocrine cells). </p>
<p>Known as <a href="https://www.ncbi.nlm.nih.gov/pubmed/11762342">neuroendocrine differentiation</a>, the changed cells are resistant to chemotherapy and radiation treatment. This has been observed with prostate, lung and coloerectal cancers, and no drug currently exists to specifically target the process. </p>
<h2>Personalised medicine</h2>
<p>So how can we overcome the challenge presented by tumour evolution? Peter Nowell <a href="https://www.ncbi.nlm.nih.gov/pubmed/959840">recognised</a> in 1976 that this would necessitate “individual specific therapy”. Forty years later, the age of personalised medicine that this pre-empted is now well underway. </p>
<p>The first cancer treatment to specifically target the effects of tumour evolution was <a href="http://www.nhs.uk/Conditions/herceptin/Pages/introduction.aspx">Herceptin</a>, which was originally approved for clinical use in the late 1990s. Herceptin is a drug that specifically targets a <a href="https://www.breastcancercare.org.uk/information-support/facing-breast-cancer/diagnosed-breast-cancer/diagnosis/her2">protein called HER2</a>, which is a key driver of some breast cancers. It is considered an individual therapy because HER2 levels are <a href="https://www.ncbi.nlm.nih.gov/pubmed/23320171">particularly high</a> in about 20% to 30% of breast cancers; and was the first of <a href="https://theconversation.com/monoclonal-antibodies-the-invisible-allies-that-changed-the-face-of-medicine-45807">a class</a> of what are known as <a href="http://www.nature.com/milestones/milecancer/full/milecancer24.html">molecular-targeted cancer therapies</a>. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/170796/original/file-20170524-31352-hmz9sy.jpg?ixlib=rb-1.1.0&amp;q=45&amp;auto=format&amp;w=1000&amp;fit=clip"><img alt="" src="https://images.theconversation.com/files/170796/original/file-20170524-31352-hmz9sy.jpg?ixlib=rb-1.1.0&amp;q=45&amp;auto=format&amp;w=754&amp;fit=clip" srcset="https://images.theconversation.com/files/170796/original/file-20170524-31352-hmz9sy.jpg?ixlib=rb-1.1.0&amp;q=45&amp;auto=format&amp;w=600&amp;h=400&amp;fit=crop&amp;dpr=1 600w, https://images.theconversation.com/files/170796/original/file-20170524-31352-hmz9sy.jpg?ixlib=rb-1.1.0&amp;q=30&amp;auto=format&amp;w=600&amp;h=400&amp;fit=crop&amp;dpr=2 1200w, https://images.theconversation.com/files/170796/original/file-20170524-31352-hmz9sy.jpg?ixlib=rb-1.1.0&amp;q=15&amp;auto=format&amp;w=600&amp;h=400&amp;fit=crop&amp;dpr=3 1800w, https://images.theconversation.com/files/170796/original/file-20170524-31352-hmz9sy.jpg?ixlib=rb-1.1.0&amp;q=45&amp;auto=format&amp;w=754&amp;h=503&amp;fit=crop&amp;dpr=1 754w, https://images.theconversation.com/files/170796/original/file-20170524-31352-hmz9sy.jpg?ixlib=rb-1.1.0&amp;q=30&amp;auto=format&amp;w=754&amp;h=503&amp;fit=crop&amp;dpr=2 1508w, https://images.theconversation.com/files/170796/original/file-20170524-31352-hmz9sy.jpg?ixlib=rb-1.1.0&amp;q=15&amp;auto=format&amp;w=754&amp;h=503&amp;fit=crop&amp;dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Cell membrane staining in patient where HER2 is driving the cancer.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/breast-cancer-awareness-immunohistochemistry-her2-shows-557300347?src=LnkSsqElR7bKPaWjCbaDBA-1-1">David Litman</a></span>
</figcaption>
</figure>
<p>Herceptin works by sticking to HER2, which prevents the protein from causing cancer growth. Unfortunately, of those who respond well to the drug, around 70% will <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3376449/">still progress</a> to metastatic disease within a year of treatment. </p>
<p>The problem is that the drug is often neutralised itself by tumour evolution, in this case from mutations to HER2 “cutting off” the part that Herceptin needs to stick to. In addition, sometimes levels of another protein called HER3 increase to compensate for the loss of effective HER2. HER3 can itself drive cancer growth and Herceptin is unable to stick to it. </p>
<p>These two examples of Herceptin resistance are typical of how cancer cells operate: they can both benefit from direct mutations to their DNA (in this case in relation to HER2), but also to influence which genes are “switched on or off” (in this case switching on HER3). We describe these as <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2802667/">epigenetic changes</a>, meaning they are “above genetics”.</p>
<p>To overcome these difficulties, cancer research has had to look elsewhere. One exciting new approach involves predicting the course of an individual’s tumour evolution by analysing tumour DNA circulating in the blood. </p>
<p>These “<a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4356857/">liquid biopsies</a>” make it possible to monitor how a patient is responding to a treatment in real time and to detect at an extremely early stage when cancers are either asserting themselves or “coming back”. We have recently seen promising results <a href="http://www.nature.com/nature/journal/vaap/ncurrent/full/nature22364.html">in relation to</a> early-stage tumour evolution in lung cancer, for instance. </p>
<p>Also promising is immunotherapy, including a new treatment for prostate cancer sufferers called <a href="http://www.provenge.com">Provenge</a>. It works by reprogramming the patient’s immune system by taking a specific type of immune cell out of their body and incubating it with a protein that is typically found on the surface of prostate cancer cells. When the cells are returned to the body, they can effectively “teach” the body how to attack its own tumour. </p>
<p>Though Provenge is not a cure for the metastatic castrate-resistant prostate cancer that I mentioned earlier, it does extend patients’ survival time <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4279604/">by about</a> 25%, and the side effects are milder than chemotherapy and radiotherapy. </p>
<p>Other immunotherapy treatments in development are similarly geared towards extending survival times rather than “cure”. They are viewed within cancer research as the biggest breakthrough to have made it past clinical trials and be approved as treatments. </p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/170838/original/file-20170524-31339-1367tnh.jpg?ixlib=rb-1.1.0&amp;q=45&amp;auto=format&amp;w=1000&amp;fit=clip"><img alt="" src="https://images.theconversation.com/files/170838/original/file-20170524-31339-1367tnh.jpg?ixlib=rb-1.1.0&amp;q=45&amp;auto=format&amp;w=754&amp;fit=clip" srcset="https://images.theconversation.com/files/170838/original/file-20170524-31339-1367tnh.jpg?ixlib=rb-1.1.0&amp;q=45&amp;auto=format&amp;w=600&amp;h=400&amp;fit=crop&amp;dpr=1 600w, https://images.theconversation.com/files/170838/original/file-20170524-31339-1367tnh.jpg?ixlib=rb-1.1.0&amp;q=30&amp;auto=format&amp;w=600&amp;h=400&amp;fit=crop&amp;dpr=2 1200w, https://images.theconversation.com/files/170838/original/file-20170524-31339-1367tnh.jpg?ixlib=rb-1.1.0&amp;q=15&amp;auto=format&amp;w=600&amp;h=400&amp;fit=crop&amp;dpr=3 1800w, https://images.theconversation.com/files/170838/original/file-20170524-31339-1367tnh.jpg?ixlib=rb-1.1.0&amp;q=45&amp;auto=format&amp;w=754&amp;h=503&amp;fit=crop&amp;dpr=1 754w, https://images.theconversation.com/files/170838/original/file-20170524-31339-1367tnh.jpg?ixlib=rb-1.1.0&amp;q=30&amp;auto=format&amp;w=754&amp;h=503&amp;fit=crop&amp;dpr=2 1508w, https://images.theconversation.com/files/170838/original/file-20170524-31339-1367tnh.jpg?ixlib=rb-1.1.0&amp;q=15&amp;auto=format&amp;w=754&amp;h=503&amp;fit=crop&amp;dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Great white hope: immunotherapy.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/close-patient-receiving-injection-hospital-244312546?src=NHvE0ubsykyntQc-kV02BQ-1-0">Wavebreakmedia</a></span>
</figcaption>
</figure>
<p>As our knowledge of specific kinds of tumour evolution in different cancers continues to progress, personalised treatment strategies like these are likely to become increasingly common. The costs will probably significantly decrease in parallel, which will take them mainstream – at present, for instance, Provenge has been <a href="https://prostatecanceruk.org/about-us/news-and-views/2015/3/can-we-use-the-body-s-defence-force-to-fight-prostate-cancer">deemed too expensive</a> for use on the NHS. </p>
<p>We are talking about no less than a revolution in cancer therapy in the coming decades. Cancer survival <a href="http://www.cancerresearchuk.org/health-professional/cancer-statistics/survival">rates have</a> already more than doubled over the last 40 years from 24% to 50% of all diagnoses in the UK. If the promise of personalised therapies bears out, there is every reason to expect those cancer survival rates to keep on climbing.</p><img src="https://counter.theconversation.com/content/78208/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Joe Sutton does not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>Tumour evolution was first identified 40 years ago. We're finally making good progress with it.Joe Sutton, PhD Researcher, Molecular Biology, Edinburgh Napier UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/742902017-05-16T10:44:21Z2017-05-16T10:44:21ZInfertility in men could point to more serious health problems later in life<figure><img src="https://images.theconversation.com/files/168601/original/file-20170509-11012-6mvfri.jpg?ixlib=rb-1.1.0&amp;q=45&amp;auto=format&amp;w=496&amp;fit=clip" /><figcaption><span class="caption">
</span> <span class="attribution"><a class="source" href="https://www.shutterstock.com/download/confirm/319477082?src=aqvp7kIgjeFnhxnlYnD68w-1-1&amp;size=medium_jpg">Sebastian Kaulitzki/Shutterstock</a></span></figcaption></figure><p>Poor sperm quality affects about <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3391374/figure/fig2/">one in ten men</a> and may lead to fertility problems. These men also have an increased risk of <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4744156/">developing testicular cancer</a>, which is the most common malignant disease of young males. And, even if they don’t develop testicular cancer, men with poor sperm quality <a href="https://www.ncbi.nlm.nih.gov/pubmed/19635736">tend to die younger</a> than men who don’t have fertility problems.</p>
<p>Couples who can’t achieve pregnancy usually go to fertility clinics for treatment. At these clinics, emphasis is put on deciding whether the couple needs assisted reproduction or not, and, if so, to choose between different methods (such as <a href="http://www.nhs.uk/Conditions/IVF/Pages/Introduction.aspx">IVF</a>, <a href="http://www.nhs.uk/Conditions/Artificial-insemination/Pages/Introduction.aspx">IUI</a>, or <a href="http://www.uhcw.nhs.uk/ivf/treatments/icsi">ICSI</a>) for doing this. In most cases, these treatments lead to pregnancy and a live birth. So the problem seems to be solved. But if infertility is an early symptom of an underlying disease in the man, fertility clinics won’t pick it up. </p>
<h2>Missed opportunity</h2>
<p>Testicular cancer is easy to detect. In men seeking treatment for fertility problems, a simple ultrasound scan of the testes can reveal early cancer, so a life-threatening tumour can be prevented. If detected, <a href="https://www.cancer.org/cancer/testicular-cancer/detection-diagnosis-staging/survival-rates.html">95% of all cases can be cured</a>. But, unfortunately, testicular ultrasound scans are rarely performed at fertility clinics as the focus tends to be on sperm numbers and which method of assisted reproduction to use.</p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/168614/original/file-20170509-11026-y5o8a6.jpg?ixlib=rb-1.1.0&amp;q=45&amp;auto=format&amp;w=754&amp;fit=clip" srcset="https://images.theconversation.com/files/168614/original/file-20170509-11026-y5o8a6.jpg?ixlib=rb-1.1.0&amp;q=45&amp;auto=format&amp;w=600&amp;h=400&amp;fit=crop&amp;dpr=1 600w, https://images.theconversation.com/files/168614/original/file-20170509-11026-y5o8a6.jpg?ixlib=rb-1.1.0&amp;q=30&amp;auto=format&amp;w=600&amp;h=400&amp;fit=crop&amp;dpr=2 1200w, https://images.theconversation.com/files/168614/original/file-20170509-11026-y5o8a6.jpg?ixlib=rb-1.1.0&amp;q=15&amp;auto=format&amp;w=600&amp;h=400&amp;fit=crop&amp;dpr=3 1800w, https://images.theconversation.com/files/168614/original/file-20170509-11026-y5o8a6.jpg?ixlib=rb-1.1.0&amp;q=45&amp;auto=format&amp;w=754&amp;h=503&amp;fit=crop&amp;dpr=1 754w, https://images.theconversation.com/files/168614/original/file-20170509-11026-y5o8a6.jpg?ixlib=rb-1.1.0&amp;q=30&amp;auto=format&amp;w=754&amp;h=503&amp;fit=crop&amp;dpr=2 1508w, https://images.theconversation.com/files/168614/original/file-20170509-11026-y5o8a6.jpg?ixlib=rb-1.1.0&amp;q=15&amp;auto=format&amp;w=754&amp;h=503&amp;fit=crop&amp;dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">An ultrasound scan could pick up most cases of testicular cancer.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/download/confirm/536840995?src=dnt7EOptKNCSUihRJnqAwA-1-0&amp;size=medium_jpg">Thomas Andreas/Shutterstock</a></span>
</figcaption>
</figure>
<p>And testicular cancer is not the only threat to young infertile men’s health. <a href="https://www.ncbi.nlm.nih.gov/pubmed/26674559">Serious health problems</a>, such as metabolic syndrome (high blood pressure, high blood sugar and obesity), type 2 diabetes and loss of bone mass are also much more common conditions among infertile men. These disorders are possible to prevent, but if left untreated often lead to premature death.</p>
<h2>A possible culprit</h2>
<p>At Lund University in Malmö, Sweden, we have – together with other research groups – made a number of studies focusing on the link between male fertility problems and subsequent risk of serious diseases. We cannot yet explain the causes, but testosterone deficiency is a strong candidate. My research team found that <a href="https://www.ncbi.nlm.nih.gov/pubmed/26857217">30% of all men with impaired semen quality</a> have low testosterone levels. And men totally lacking the hormone have early signs of diabetes and bone loss. </p>
<p>We recently conducted <a href="https://www.ncbi.nlm.nih.gov/pubmed/27993426">a study</a> in which we investigated almost 4,000 men below the age of 50 and who had had their testosterone measured 25 years ago. We found that the risk of dying at a young age was doubled among those with low testosterone levels compared with men with normal levels of this hormone. </p>
<p>Although testosterone treatment may not necessarily be the best preventive measure, these findings makes it possible to identify men at high risk so that they can be advised about lifestyle changes, such as losing weight or quitting smoking – lifestyle changes that will help reduce the risk of developing type 2 diabetes, cardiovascular disease and osteoporosis. </p>
<p>A relatively high proportion of men get in touch with their doctor about infertility problems and, as they represent a high-risk group for some of the most common diseases occurring later in life, perhaps it is time to change the routines for managing them. With the knowledge we now have regarding these men’s health, the least we can demand from doctors is to identify those who are at risk of serious diseases after they have become fathers. This is cheap and only requires simple tests. It is no longer enough to just evaluate the number of sperm.</p><img src="https://counter.theconversation.com/content/74290/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span><a href="mailto:aleksander.giwercman@med.lu.se">aleksander.giwercman@med.lu.se</a> receives funding from
Swedish Research Council
Swedish Cancer Society
Swedish Childhood Cancer Society
Swedish Governmental Fund for Clinical Research
Bayer Pharmaceuticals
Ferring Pharmaceuticals</span></em></p><p class="fine-print"><em><span>Yvonne Lundberg Giwercman does not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>Doctors should examine more than just sperm count in infertile men.Aleksander Giwercman, Professor of Reproductive Medicine, Lund UniversityYvonne Lundberg Giwercman, Associate Professor in Experimental Urology, Lund UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/715272017-03-09T04:20:03Z2017-03-09T04:20:03ZIf men are favored in our society, why do they die younger than women?<figure><img src="https://images.theconversation.com/files/160060/original/image-20170308-24192-1ydc59e.jpg?ixlib=rb-1.1.0&amp;q=45&amp;auto=format&amp;w=496&amp;fit=clip" /><figcaption><span class="caption">Older man having chest pain, which could signal a heart attack.</span> <span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/closeup-older-warehouse-worker-having-heart-254247421?src=C-ZAI2UGtXjw5w5NJPtIlQ-1-0">From www.shutterstock.com</a></span></figcaption></figure><p>Women experience higher <a href="https://theconversation.com/why-stress-is-more-likely-to-cause-depression-in-men-than-in-women-57624">stress</a>, more <a href="http://www.cwhn.ca/en/resources/primers/chronicdisease">chronic disease</a>, more <a href="http://www.mayoclinic.org/diseases-conditions/depression/in-depth/depression/art-20047725">depression</a>, more <a href="http://www.cnn.com/2016/06/08/health/women-anxiety-disorders/">anxiety</a> and are more likely to be victims of <a href="http://www.hhri.org/thematic/gender_based_violence.html">violence</a>. Women earn less than men, and in many countries they don’t have the same human rights as <a href="http://www.unfpa.org/resources/human-rights-women">men</a>. </p>
<p>Despite the <a href="http://www.iwpr.org/initiatives/pay-equity-and-discrimination#sthash.k3LXMVNP.dpuf">social inequality</a> women experience, they live longer than men. This is the case without a single <a href="http://www.prb.org/DataFinder/Topic/Rankings.aspx?ind=6">exception</a>, in all countries.</p>
<p>For instance, in the U.S. in 2015 female full-time workers made only 80 cents for every dollar earned by men, indicating a <a href="http://www.iwpr.org/initiatives/pay-equity-and-discrimination#sthash.k3LXMVNP.dpuf">20 percent</a> gender wage gap. Yet, life expectancy for women in the U.S. is <a href="http://www.usatoday.com/story/news/nation/2014/10/08/us-life-expectancy-hits-record-high/16874039/">81.2 years</a> compared to 76.4 for males.</p>
<p>Even in countries with larger wage gaps or extreme gender inequalities, <a href="http://www.unwomen.org/en/what-we-do/economic-empowerment/facts-and-figures">women live longer than men</a>.</p>
<p>As a researcher who studies <a href="http://jdmdonline.biomedcentral.com/articles/10.1186/2251-6581-13-36">cross-country</a> and <a href="http://www.iwpr.org/initiatives/pay-equity-and-discrimination#sthash.k3LXMVNP.dpuf">gender</a> differences in health, I am always fascinated by how the intersection of these factors influences health. So why do women live longer, despite their lower social rank and worse health?</p>
<h2>Is it basic biology?</h2>
<p>Gender refers to social aspects of being a woman or a man such as social stress, opportunity and social expectations. </p>
<p>Sex, on the other hand, refers to biology. Biology can contribute to this difference in life expectancy. Women have biological advantages that let them <a href="https://www.scientificamerican.com/article/why-is-life-expectancy-lo/">live longer</a>. </p>
<p>For instance, estrogen <a href="https://www.cmu.edu/CSR/case_studies/women_live_longer.html">benefits women</a> because it lowers low-density lipoprotein cholesterol (or LDL, what you may know as “bad” cholesterol) and increases high-density lipoprotein cholesterol (or HDL, the “good” cholesterol), which reduces cardiovascular risk.</p>
<p>Testosterone, on the other hand, increases blood levels of the bad cholesterol and decreases levels of good cholesterol. This puts men at greater risk of hypertension, heart disease and stroke. </p>
<p>When it comes to chronic diseases, women tend to have more of them. But there is a caveat here. Men and women have different types of chronic disease. Women have more nonfatal, chronic conditions, while men have more fatal <a href="http://www.paho.org/hq/index.php?option=com_content&amp;view=article&amp;id=7732%3A2011-women-men-face-different-chronic-disease-risks&amp;catid=4045%3Achronic-diseases-news&amp;Itemid=40276&amp;lang=en">conditions</a>. </p>
<p>For example, women have more arthritis, which does not kill, even if disabling. In contrast, men are at higher risk of chronic diseases that are leading <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3018605/">killers</a>. Heart disease starts 10 years earlier in men than <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3018605/">women</a>. </p>
<p>So, biological differences play a role in this life expectancy gap, but gender, I argue, plays a bigger role. </p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/160001/original/image-20170308-24179-1lyazed.jpg?ixlib=rb-1.1.0&amp;q=45&amp;auto=format&amp;w=754&amp;fit=clip" srcset="https://images.theconversation.com/files/160001/original/image-20170308-24179-1lyazed.jpg?ixlib=rb-1.1.0&amp;q=45&amp;auto=format&amp;w=600&amp;h=399&amp;fit=crop&amp;dpr=1 600w, https://images.theconversation.com/files/160001/original/image-20170308-24179-1lyazed.jpg?ixlib=rb-1.1.0&amp;q=30&amp;auto=format&amp;w=600&amp;h=399&amp;fit=crop&amp;dpr=2 1200w, https://images.theconversation.com/files/160001/original/image-20170308-24179-1lyazed.jpg?ixlib=rb-1.1.0&amp;q=15&amp;auto=format&amp;w=600&amp;h=399&amp;fit=crop&amp;dpr=3 1800w, https://images.theconversation.com/files/160001/original/image-20170308-24179-1lyazed.jpg?ixlib=rb-1.1.0&amp;q=45&amp;auto=format&amp;w=754&amp;h=501&amp;fit=crop&amp;dpr=1 754w, https://images.theconversation.com/files/160001/original/image-20170308-24179-1lyazed.jpg?ixlib=rb-1.1.0&amp;q=30&amp;auto=format&amp;w=754&amp;h=501&amp;fit=crop&amp;dpr=2 1508w, https://images.theconversation.com/files/160001/original/image-20170308-24179-1lyazed.jpg?ixlib=rb-1.1.0&amp;q=15&amp;auto=format&amp;w=754&amp;h=501&amp;fit=crop&amp;dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Women take more care of their health.</span>
<span class="attribution"><a class="source" href="https://www.shutterstock.com/image-photo/patient-having-consultation-doctor-office-536438233?src=cl3xhg19Hd3TSxz_c9CaWw-1-29">Doctor and patient image via www.shutterstock.com.</a></span>
</figcaption>
</figure>
<h2>Women are more health aware</h2>
<p>Studies have shown that, in general, women are more <a href="http://www.womenshealthct.com/about-us/news/view/study-shows-women-over-30-more-health-conscious">health conscious</a>, and they have <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3604146/">higher awareness</a> of their physical and mental symptoms. These all result in healthier lifestyles and better health care use. Women also communicate better about their problems, which helps the <a href="https://www.natcom.org/CommCurrentsArticle.aspx?id=749">process</a> of <a href="https://www.ncbi.nlm.nih.gov/pubmed/12477605">diagnosis</a>.</p>
<p>Being a man means <a href="http://journals.lww.com/jaids/Fulltext/2015/07010/Gender_Differences_in_Adherence_and_Response_to.16.aspx">delayed</a> initiation of treatment of any kind. <a href="http://journals.lww.com/jaids/Fulltext/2015/07010/Gender_Differences_in_Adherence_and_Response_to.16.aspx">Men are less adherent to treatment</a>. </p>
<p>These issues collectively cause males to be vulnerable to therapeutic <a href="http://journals.lww.com/jaids/Fulltext/2015/07010/Gender_Differences_in_Adherence_and_Response_to.16.aspx">failure</a>.</p>
<p>Masculinity is a socially learned construct, and it can have <a href="http://www.chicagotribune.com/sns-health-men-masculinity-story.html">unhealthy</a> effects. Many men define <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2998494/">unhealthy and risky behaviors</a> as masculine, while they see health care use and health-promoting behaviors as feminine.</p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/160004/original/image-20170308-24215-1x93bt9.jpg?ixlib=rb-1.1.0&amp;q=45&amp;auto=format&amp;w=754&amp;fit=clip" srcset="https://images.theconversation.com/files/160004/original/image-20170308-24215-1x93bt9.jpg?ixlib=rb-1.1.0&amp;q=45&amp;auto=format&amp;w=600&amp;h=260&amp;fit=crop&amp;dpr=1 600w, https://images.theconversation.com/files/160004/original/image-20170308-24215-1x93bt9.jpg?ixlib=rb-1.1.0&amp;q=30&amp;auto=format&amp;w=600&amp;h=260&amp;fit=crop&amp;dpr=2 1200w, https://images.theconversation.com/files/160004/original/image-20170308-24215-1x93bt9.jpg?ixlib=rb-1.1.0&amp;q=15&amp;auto=format&amp;w=600&amp;h=260&amp;fit=crop&amp;dpr=3 1800w, https://images.theconversation.com/files/160004/original/image-20170308-24215-1x93bt9.jpg?ixlib=rb-1.1.0&amp;q=45&amp;auto=format&amp;w=754&amp;h=326&amp;fit=crop&amp;dpr=1 754w, https://images.theconversation.com/files/160004/original/image-20170308-24215-1x93bt9.jpg?ixlib=rb-1.1.0&amp;q=30&amp;auto=format&amp;w=754&amp;h=326&amp;fit=crop&amp;dpr=2 1508w, https://images.theconversation.com/files/160004/original/image-20170308-24215-1x93bt9.jpg?ixlib=rb-1.1.0&amp;q=15&amp;auto=format&amp;w=754&amp;h=326&amp;fit=crop&amp;dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Men are riskier drivers.</span>
<span class="attribution"><a class="source" href="https://www.flickr.com/photos/thomashawk/12235747/in/photolist-25Hga-9dLfdu-awukxB-4z9P3Y-ihj5xp-5kq9DE-9dhUBb-9axXsz-aUXTD8-aE2nQQ-4z5yTe-7JFbqB-nwyc9A-9dhUnj-czfSzC-5Y5tKY-6fEPKW-nwxShC-91XqS9-nwgwad-9dLkRj-nwgzoh-9bFHqi-5Bzogq-9b5CuL-4LJS3G-9bYUp7-dmP9Qh-nwfNa1-9dLepw-i1eKb1-nwg3TE-i1exFj-9b9HsX-nwg3dS-9bFhde-5keeZU-nutHTf-9bFmoF-i1fnEc-9aWsPY-9dLn2u-62v2ZB-9bFnW4-9aSFUn-9bJtiC-9aA3jC-9dhMAU-9bFGZ4-9aWsQ3">Thomas Hawk/flickr</a>, <a class="license" href="http://creativecommons.org/licenses/by-nc/4.0/">CC BY-NC</a></span>
</figcaption>
</figure>
<h2>Risky behavior and sensation-seeking</h2>
<p>Testosterone puts men at risk biologically, but it also puts men at risk behaviorally. It increases aggressiveness, and, in a cascading effect, results in higher death rate from <a href="http://www.prb.org/Publications/Articles/2007/genderdisparities.aspx">accidents and homicide</a>. </p>
<p>My colleague and I followed more than 250 youth and found that baseline testestrone predicts future <a href="http://traumamon.com/?page=article&amp;article_id=18040">violent</a> behaviors. </p>
<p>Women systematically overestimate risk of any type, while men consistently <a href="http://journal.sjdm.org/jdm06016.pdf">underestimate</a> it. This pattern has been observed regardless of the context. These include examples ranging from crossing a road to perception of risk of volcano, smoking or a terrorist attack. Among <a href="https://halshs.archives-ouvertes.fr/hal-00851149/document">pedestrians</a>, males violate more rules than females. Among drivers, men more commonly <a href="http://www.sirc.org/publik/driving.pdf">break the rules</a>. </p>
<p>Accidents, like motor vehicle crashes, are far more common among <a href="https://www.cdc.gov/mmwr/preview/mmwrhtml/mm6111a7.htm?s_cid=mm6111a7_w">men</a> than women. This is due in part to men’s greater risk-taking, underestimation of risk, sensation-seeking, and tendency to be more impulsive.</p>
<p>This difference extends to almost any task in <a href="http://journal.sjdm.org/06016/jdm06016.htm">real life</a>. This in part explains why women internalize and men <a href="https://www.drugabuse.gov/publications/research-reports/substance-use-in-women/sex-gender-differences-in-substance-use">externalize</a> (which requires low perception of risk). </p>
<p>Substance use is also more common among <a href="https://www.drugabuse.gov/publications/research-reports/substance-use-in-women/sex-gender-differences-in-substance-use">men</a> than among women. While that gap is narrowing, <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3124962/">according to a 2011 study</a>, men were 2.2 times more likely to abuse drugs than women, and 1.9 times more likely to have drug dependence.</p>
<p>Among those who have drug use problems, men tend to have more severe problems, defined by frequency of use, using more than one substance and risky behaviors such as <a href="https://www.ncbi.nlm.nih.gov/pubmed/8777737">injection</a> drug use. Men with drug use problems <a href="https://www.drugabuse.gov/publications/research-reports/substance-use-in-women/sex-gender-differences-in-substance-use">seek care</a> later than women do. Men also drive under the influence of drugs and <a href="http://www.drunkdrivingstats.org/menversuswomendrunkdrivingstatistics.html">alcohol</a> more frequently than women. Men are responsible for four out of every five cases of driving under the influence of a drug or alcohol.</p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/160006/original/image-20170308-24192-e2paio.jpg?ixlib=rb-1.1.0&amp;q=45&amp;auto=format&amp;w=754&amp;fit=clip" srcset="https://images.theconversation.com/files/160006/original/image-20170308-24192-e2paio.jpg?ixlib=rb-1.1.0&amp;q=45&amp;auto=format&amp;w=600&amp;h=450&amp;fit=crop&amp;dpr=1 600w, https://images.theconversation.com/files/160006/original/image-20170308-24192-e2paio.jpg?ixlib=rb-1.1.0&amp;q=30&amp;auto=format&amp;w=600&amp;h=450&amp;fit=crop&amp;dpr=2 1200w, https://images.theconversation.com/files/160006/original/image-20170308-24192-e2paio.jpg?ixlib=rb-1.1.0&amp;q=15&amp;auto=format&amp;w=600&amp;h=450&amp;fit=crop&amp;dpr=3 1800w, https://images.theconversation.com/files/160006/original/image-20170308-24192-e2paio.jpg?ixlib=rb-1.1.0&amp;q=45&amp;auto=format&amp;w=754&amp;h=566&amp;fit=crop&amp;dpr=1 754w, https://images.theconversation.com/files/160006/original/image-20170308-24192-e2paio.jpg?ixlib=rb-1.1.0&amp;q=30&amp;auto=format&amp;w=754&amp;h=566&amp;fit=crop&amp;dpr=2 1508w, https://images.theconversation.com/files/160006/original/image-20170308-24192-e2paio.jpg?ixlib=rb-1.1.0&amp;q=15&amp;auto=format&amp;w=754&amp;h=566&amp;fit=crop&amp;dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Substance abuse is more common among men.</span>
<span class="attribution"><a class="source" href="https://www.flickr.com/photos/55267995@N04/16592440438/in/photolist-rhdAth-7CmUbg-ah1vQp-i87FGu-7StchM-dHRJNw-mL8vog-zodspJ-7G83vW-bsfA6y-ixoa3t-ixohc7-fK6KSU-bc7QGg-9ptQgC-jZtagk-bsfAtq-83y5ML-bnd5Vv-ixofs5-dGvzQb-5XqGDk-81xqFa-6uRGL-d3EB3G-aa6c8m-5K1uUk-5tFxF-6DzenX-a7Nipf-bPP812-9nu73y-6FXGXf-8YUVkT-nTNdJA-e6ccQ9-ec3x67-81xqvK-23M3tr-Dxv4P-dsg6Nk-BBRyC3-dUFyRu-aHfcga-t6YFoj-78DPbS-4veNS3-NwT165-QBhjrK-4P73ei">ctj71081/flickr</a>, <a class="license" href="http://creativecommons.org/licenses/by-sa/4.0/">CC BY-SA</a></span>
</figcaption>
</figure>
<p>So why do men have a higher tendency to abuse illicit drugs and alcohol than women? </p>
<p>This is in part due to <a href="http://europepmc.org/articles/PMC3757272">sensation-seeking</a>, which makes some men search for experiences and feelings that are varied, novel, complex and intense. Higher <a href="https://www.ncbi.nlm.nih.gov/pubmed/9153092">acceptability</a> for men of risky behaviors, <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3282519/">peer pressure</a> and <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2756494/">gender roles</a> also have a role. Although some of this may be due to testosterone <a href="https://www.ncbi.nlm.nih.gov/pubmed/20026092">levels</a>, a considerable part of it is due to learned <a href="http://link.springer.com/article/10.1007/s11199-007-9214-4">gender roles</a>. </p>
<p>In addition to higher sensation-seeking, men have more <a href="https://eric.ed.gov/?id=EJ911320">impulsive traits</a> and have higher thresholds for <a href="https://eric.ed.gov/?id=EJ911320">punishment</a>.</p>
<p>And our previous research has shown that <a href="http://psycnet.apa.org/journals/men/14/1/47/">masculinity</a> plays a role for depression and alcohol use.</p>
<h2>Suicide</h2>
<p>In <a href="https://www.ncbi.nlm.nih.gov/pubmed/9675500">most countries</a>, men are more likely to die by suicide. In the <a href="https://afsp.org/about-suicide/suicide-statistics/">United States</a>, for example, men are 3.5 times more likely than women to die from suicide. This is mainly because men use <a href="http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0129062">more lethal methods</a> for suicide, such as <a href="https://www.ncbi.nlm.nih.gov/pubmed/11079640">firearms</a>.</p>
<p>In the U.S. most suicides are <a href="http://www.bbc.com/news/world-us-canada-36116166">white men</a>. In fact, suicides among this group are one reason why mortality for middle-aged white American men is <a href="http://www.nytimes.com/2015/11/03/health/death-rates-rising-for-middle-aged-white-americans-study-finds.html?_r=0">increasing</a>.</p>
<p>One reason behind the high suicide rate among men is the <a href="http://www.huffingtonpost.com/entry/what-men-really-think-about-mental-health-stigma_us_55f07856e4b002d5c077a697">high stigma</a> about psychiatric disorders as well as mental health care use. So when men experience <a href="http://journal.frontiersin.org/article/10.3389/fpubh.2016.00049/full">stress</a> they are at higher risk of <a href="https://theconversation.com/why-stress-is-more-likely-to-cause-depression-in-men-than-in-women-57624">mental health problems such as depression</a> than women, possibly because they do not talk about their emotions and they do not seek care. Such a tendency to <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2875717/">avoid mental health care</a> is directly related to masculinity, gender norms and social expectations for men.</p>
<p><a href="http://www.thelancet.com/journals/lanpsy/article/PIIS2215-0366(14)00118-7/abstract">Unemployment</a> is a major cause of suicide globally and in the U.S. Unemployment may have a <a href="http://www.tandfonline.com/doi/abs/10.1080/00036840802599446">bigger role</a> as a cause of suicide for men, as it results in a larger “human capital loss” among men than women. </p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/160008/original/image-20170308-24215-zlyn5m.jpg?ixlib=rb-1.1.0&amp;q=45&amp;auto=format&amp;w=754&amp;fit=clip" srcset="https://images.theconversation.com/files/160008/original/image-20170308-24215-zlyn5m.jpg?ixlib=rb-1.1.0&amp;q=45&amp;auto=format&amp;w=600&amp;h=429&amp;fit=crop&amp;dpr=1 600w, https://images.theconversation.com/files/160008/original/image-20170308-24215-zlyn5m.jpg?ixlib=rb-1.1.0&amp;q=30&amp;auto=format&amp;w=600&amp;h=429&amp;fit=crop&amp;dpr=2 1200w, https://images.theconversation.com/files/160008/original/image-20170308-24215-zlyn5m.jpg?ixlib=rb-1.1.0&amp;q=15&amp;auto=format&amp;w=600&amp;h=429&amp;fit=crop&amp;dpr=3 1800w, https://images.theconversation.com/files/160008/original/image-20170308-24215-zlyn5m.jpg?ixlib=rb-1.1.0&amp;q=45&amp;auto=format&amp;w=754&amp;h=539&amp;fit=crop&amp;dpr=1 754w, https://images.theconversation.com/files/160008/original/image-20170308-24215-zlyn5m.jpg?ixlib=rb-1.1.0&amp;q=30&amp;auto=format&amp;w=754&amp;h=539&amp;fit=crop&amp;dpr=2 1508w, https://images.theconversation.com/files/160008/original/image-20170308-24215-zlyn5m.jpg?ixlib=rb-1.1.0&amp;q=15&amp;auto=format&amp;w=754&amp;h=539&amp;fit=crop&amp;dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Societal expectations start early.</span>
<span class="attribution"><a class="source" href="https://www.flickr.com/photos/renawgraphy/4164575815/in/photolist-7m1xii-4A5v5j-S8Y6qS-pkbviz-e7kyyt-qkmvVB-8gpNJ3-rjj3aY-d1t5Cy-e7kytB-5CMNQ2-4uHuLd-aWxiFz-5WLQRT-4aNWCm-c8j9F7-f2aQmx-7eLmoU-5nQLBm-pk8BYi-7eGt62-b6LqGx-7Kt7dA-a8bUKC-ezXtYm-d81J6-9EKkm6-ow77tu-iWVFy6-5XTDfc-5LasTm-5iikBY-6eyvhC-dXGKa5-5nJHgx-7eGr48-7eLq17-BLHi5-f2aPHe-nWBSGx-7ctciZ-8Q8L9C-bepPNz-8VKFP-4FTzWx-4NsNWs-9MgNPw-5vGhvG-eAT2q-f6wyVt">Abby Bischoff/flickr</a>, <a class="license" href="http://creativecommons.org/licenses/by-nc-nd/4.0/">CC BY-NC-ND</a></span>
</figcaption>
</figure>
<h2>Thinking about gender</h2>
<p>Our gender can determine how our parents treat us, which in turn make us learn to behave in a certain way, as dictated by societal beliefs, values, attitudes and examples. Boys and girls start facing social norms that define “masculine” and “feminine” for them from an early age. </p>
<p>Gender differences in mortality are mainly behavioral and thus preventable, as they are learned in society and manifested in behavioral and psychological ways. Although our brain is involved, it is not in our genetics. It is learned socially and it can be unlearned. </p>
<p>Gender differences are rules rather than exceptions. While in many factors, women do worse than men, in the case of life expectancy, men do worse. Theese are mainly due to a wide range of social, psychological and behavioral factors such as sensation-seeking, risk-taking traits, stigma, masculinity, worse health care use, and a tendency for externalizing behavior. Males require more self-control, stigma reduction (by mass media) and incentives to seek and use professional care.</p><img src="https://counter.theconversation.com/content/71527/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Shervin Assari does not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>Women are paid 20 percent less than men in the US but live about five years longer than men. You might be surprised at the reasons that men, on average, die at a younger age.Shervin Assari, Research Investigator of Psychiatry and Public Health, University of MichiganLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/684192016-11-28T03:23:17Z2016-11-28T03:23:17ZHealth Check: why men wake up with erections<figure><img src="https://images.theconversation.com/files/146942/original/image-20161122-24550-1gkhp4s.jpg?ixlib=rb-1.1.0&amp;q=45&amp;auto=format&amp;w=496&amp;fit=clip" /><figcaption><span class="caption">Many men are not actually aroused when they wake up erect. </span> <span class="attribution"><span class="source">from www.shutterstock.com.au</span></span></figcaption></figure><p>The morning penile erection, or as it is medically known, “nocturnal penile tumescence”, is not only an interesting physiological phenomenon, it can also tell us a lot about a patient’s sexual function.</p>
<p>Morning penile erections affect all males, even <a href="https://www.ncbi.nlm.nih.gov/pubmed/2192091">males in the womb</a> and male children. It also has a female counterpart in the less frequently discussed nocturnal clitoral erection.</p>
<h2>What causes erections?</h2>
<p>Penile erections occur in response to complex effects of the nervous system and endocrine system (the glands that secrete hormones into our system) on the blood vessels of the penis. </p>
<p>When sexually aroused, a message starts in the brain, sending chemical messages to the nerves that supply the blood vessels of the penis, allowing blood to flow into the penis. The blood is trapped in the muscles of the penis, which makes the penis expand, resulting in an erection. </p>
<p>Several hormones are involved in influencing the brain’s response, such as testosterone (the main male hormone).</p>
<p>This same mechanism can occur without the involvement of the brain, in an uncontrolled reflex action that is in the spinal cord. This explains why people with spinal cord damage can still get erections and why you can get erections when not sexually aroused.</p>
<h2>What about erections while we sleep?</h2>
<p>Nocturnal penile erections occur during Rapid Eye Movement (REM) sleep (the phase during which we dream). They occur when <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1351051/">certain areas of the brain</a> are activated. This includes areas in the brain responsible for stimulating the parasympathetic nerves (“rest and digest” nerves), suppressing the sympathetic nerves (“flight and fight” nerves) and dampening areas <a href="https://faculty.washington.edu/chudler/auto.html">producing serotonin</a> (the mood hormone).</p>
<p>Sleep is made up of several cycles of REM and non-REM (deep) sleep. During REM sleep, there is a shift in the dominant system that’s activated. We move from sympathetic (fight and flight) stimulation to parasympathetic (rest and digest) stimulation. This is not found during other parts of the sleep cycle. </p>
<p>This shift in balance drives the parasympathetic nerve response that results in the erection. This is spontaneous and does not require being awake. Some men may experience nocturnal penile tumescence during non-REM sleep as well, particularly older men. The reason for this is unclear.</p>
<p>The reason men wake up with an erection may be related to the fact we often wake up coming out of REM sleep.</p>
<p>Testosterone, which is at its highest level in the morning, has also been shown to enhance the frequency of nocturnal erections. Interestingly, testosterone has <a href="https://www.ncbi.nlm.nih.gov/pubmed/8848520">not been found to greatly impact</a> visual erotic stimuli or fantasy-induced erections. These are predominantly driven by the “reward system” of the brain which secretes dopamine.</p>
<figure class="align-center zoomable">
<a href="https://images.theconversation.com/files/147520/original/image-20161125-15325-3s9i7p.jpg?ixlib=rb-1.1.0&amp;q=45&amp;auto=format&amp;w=1000&amp;fit=clip"><img alt="" src="https://images.theconversation.com/files/147520/original/image-20161125-15325-3s9i7p.jpg?ixlib=rb-1.1.0&amp;q=45&amp;auto=format&amp;w=754&amp;fit=clip" srcset="https://images.theconversation.com/files/147520/original/image-20161125-15325-3s9i7p.jpg?ixlib=rb-1.1.0&amp;q=45&amp;auto=format&amp;w=600&amp;h=400&amp;fit=crop&amp;dpr=1 600w, https://images.theconversation.com/files/147520/original/image-20161125-15325-3s9i7p.jpg?ixlib=rb-1.1.0&amp;q=30&amp;auto=format&amp;w=600&amp;h=400&amp;fit=crop&amp;dpr=2 1200w, https://images.theconversation.com/files/147520/original/image-20161125-15325-3s9i7p.jpg?ixlib=rb-1.1.0&amp;q=15&amp;auto=format&amp;w=600&amp;h=400&amp;fit=crop&amp;dpr=3 1800w, https://images.theconversation.com/files/147520/original/image-20161125-15325-3s9i7p.jpg?ixlib=rb-1.1.0&amp;q=45&amp;auto=format&amp;w=754&amp;h=503&amp;fit=crop&amp;dpr=1 754w, https://images.theconversation.com/files/147520/original/image-20161125-15325-3s9i7p.jpg?ixlib=rb-1.1.0&amp;q=30&amp;auto=format&amp;w=754&amp;h=503&amp;fit=crop&amp;dpr=2 1508w, https://images.theconversation.com/files/147520/original/image-20161125-15325-3s9i7p.jpg?ixlib=rb-1.1.0&amp;q=15&amp;auto=format&amp;w=754&amp;h=503&amp;fit=crop&amp;dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px"></a>
<figcaption>
<span class="caption">Men don’t wake up with erections because they’ve been having sexy dreams.</span>
<span class="attribution"><span class="source">from www.shutterstock.com</span></span>
</figcaption>
</figure>
<p>Since there are several sleep cycles per night, men can have as many as five erections per night and these can last up to 20 or 30 minutes. But this is very dependent on sleep quality and so they may not occur daily. The number and quality of erections declines gradually with age but they are often present well beyond “retirement age” - attesting to the sexual well-being of older men.</p>
<p>It’s also important to highlight the counterpart phenomenon in women, which is much less researched. Pulses of blood flow in the vagina during REM sleep. The <a href="http://www.tandfonline.com/doi/abs/10.1080/00926237908403713">clitoris engorges</a> and vaginal sensitivity increases along with vaginal fluidity.</p>
<h2>What’s its purpose?</h2>
<p>It has been suggested “pitching a tent” may be a mechanism for alerting men of their full overnight bladder, as it often disappears after emptying the bladder in the morning. </p>
<p>It’s more likely the reason for the morning erection is that the unconscious sensation of the full bladder stimulates nerves that go to the spine and these respond directly by generating an erection (a spinal reflex). This may explain why the erection goes away after emptying one’s bladder.</p>
<p><a href="https://www.sciencedaily.com/releases/2008/07/080702091346.htm">Scientific studies</a> are undecided as to whether morning erections contribute to penile health. Increased oxygen in the penis at night may be beneficial for the health of the muscle tissues that make up the penis.</p>
<h2>What does it mean if you don’t get one?</h2>
<p>Loss of nocturnal erection can be a useful marker of common diseases affecting erectile function. One example is in <a href="http://psycnet.apa.org/psycinfo/1978-32025-001">diabetics</a> where the lack of morning erections may be associated with erectile dysfunction due to poor nerve or blood supply to the penis. In this case, there’s a poor response to the messages sent from the brain during sleep which generate nocturnal erections. </p>
<p>It is thought nocturnal erections can be used as a marker of an anatomical ability to get an erection (a sign that the essential body bits are working), as it was thought to be independent of psychological factors that affect erections while awake. <a href="http://www.sciencedirect.com/science/article/pii/0006322388901199">Studies have suggested</a>, however, that mental health disorders such as severe depression can affect nocturnal erections. Thus its absence is <a href="http://jamanetwork.com/journals/jamapsychiatry/article-abstract/492087">not necessarily a marker</a> of disease or low testosterone levels.</p>
<p>The frequency of morning erections and erection quality <a href="http://www.sciencedirect.com/science/article/pii/S0090429500008414">has also been shown to</a> increase slightly in men taking medications for erectile dysfunction such as Viagra.</p>
<h2>So is all this morning action good news?</h2>
<p>While some men will put their nocturnal erections to good use, many men are not aroused when they have them and tummy sleepers might find them a nuisance.</p>
<p>Since good heart health is associated with an ability to have erections, the presence of nocturnal erections is generally accepted to be good news. Maintaining a healthy lifestyle is important in <a href="https://www.ncbi.nlm.nih.gov/pubmed/22072232">avoiding and even reversing</a> erectile dysfunction, so it’s important to remember to eat healthily, maintain a healthy weight, exercise and <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4291878/">avoid smoking and alcohol</a>.</p><img src="https://counter.theconversation.com/content/68419/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Sergio Diez Alvarez no recibe salario, ni ejerce labores de consultoría, ni posee acciones, ni recibe financiación de ninguna compañía u organización que pueda obtener beneficio de este artículo, y ha declarado carecer de vínculos relevantes más allá del cargo académico citado.</span></em></p>Morning penile erections affect all males, even males in the womb and male children.Sergio Diez Alvarez, Director Of Medicine, The Maitland and Kurri Kurri Hospital, University of NewcastleLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/680052016-11-02T09:40:07Z2016-11-02T09:40:07ZDoes a pudgy 'dad bod' really make men live longer? Here's the science<figure><img src="https://images.theconversation.com/files/144102/original/image-20161101-27102-19bpyg6.jpg?ixlib=rb-1.1.0&amp;q=45&amp;auto=format&amp;w=496&amp;fit=clip" /><figcaption><span class="caption">Big daddies are also more attractive ... apparently.</span> <span class="attribution"><a class="source" href="http://www.shutterstock.com/pic-410729206/stock-photo-fat-man-eating-potato-chips.html?src=KZUdVEw66hPPkyCVoZ-Nig-1-19">Shutterstock</a></span></figcaption></figure><p>The <a href="http://www.mirror.co.uk/3am/celebrity-news/what-dad-bod-introducing-physique-5637231">“dad bod”</a>, it seems, is <a href="https://www.msn.com/en-au/health/medical/beer-bellies-are-in-biceps-are-out-introducing-the-dad-bod/ar-BBjewl7">in vogue</a>. <a href="http://press.princeton.edu/titles/10807.html">And now a new book</a> claims that gaining weight after fatherhood makes men <a href="https://www.theguardian.com/lifeandstyle/shortcuts/2016/oct/31/pudgy-dads-more-attractive-how-men-age">healthier, more attractive and more likely to live longer than their “skinny” counterparts</a>. </p>
<p>The author, Richard Bribiescas, professor of anthropology and deputy provost at Yale University, claims that this is likely due in part to the <a href="http://press.endocrine.org/doi/10.1210/jc.2007-1972?url_ver=Z39.88-2003&amp;rfr_id=ori:rid:crossref.org&amp;rfr_dat=cr_pub%3dpubmed">decreasing testosterone levels seen in older men</a>. <a href="http://www.telegraph.co.uk/news/2016/10/31/chubby-older-fathers-are-more-attractive-to-women-and-live-longe/">He writes</a>:</p>
<blockquote>
<p>[One] effect of lower testosterone levels is loss of muscle mass and increases in fat mass. This change in body composition not only causes men to shop for more comfortable trousers but also facilitates increased survivorship and, hypothetically, a hormonal milieu that would more effectively promote and support paternal investment.</p>
</blockquote>
<p>But is there actually any solid science behind the idea that lower levels of testosterone – and a bit of a tummy – can make men healthier?</p>
<p>There exists a complex relationship between our body composition, the relative amounts of fat and muscle that we have, and how we age. While accurately measuring biological ageing is actually quite difficult, studies have nevertheless shown that having too much body fat <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2805851/">can prematurely age us</a> and that maintaining our levels of muscle mass could have <a href="https://www.ncbi.nlm.nih.gov/pubmed/26675777">the opposite effect</a>. It is certainly true that frailty, a syndrome in which older adults carry an increased risk of poor health outcomes <a href="http://onlinelibrary.wiley.com/doi/10.1002/oby.21013/abstract">is increased in people who carry too much body fat</a>. </p>
<h2>Testosterone and ageing</h2>
<p>But what about testosterone? Testosterone is a steroid hormone that in men is produced by the testes. Alongside governing male sexual characteristics, it also <a href="http://onlinelibrary.wiley.com/doi/10.1111/j.1365-2265.2005.02339.x/full">controls body composition</a>, with lower levels – <a href="http://elitemensguide.com/testosterone-levels-by-age/">which naturally occur as we age</a> –being associated with less muscle and more fat. It is this very change in body composition that these new claims of vitality are based upon. </p>
<p>Beyond this, there is actually some evidence that testosterone is involved in the ageing process. The most profound evidence that testosterone can affect how we age comes from studies of people who have none: eunuchs or castrati. These men, who have had their testicles removed, <a href="http://www.sciencedirect.com/science/article/pii/S0960982212007129">outlive their non-castrated counterparts by as much as 20 years</a>, suggesting that the levels of this hormone may have a profound effect on the ageing process. </p>
<p>The precise reasons for this impressive effect are not very clear, but suggested mechanisms have included <a href="http://www.sciencedirect.com/science/article/pii/S0003347204001575">an increased ability to fight off infection</a> and a <a href="http://onlinelibrary.wiley.com/doi/10.3322/canjclin.22.4.232/pdf">reduced risk of developing prostate cancer</a>, although the latter is a <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4647137/">controversial link</a>. It is unlikely the effect is related to cardiovascular health as low testosterone levels are also associated with cardiovascular risk factors and testosterone replacement therapy (TrT) has been shown to improve <a href="https://www.ncbi.nlm.nih.gov/pubmed/19011291">angina pectoris</a></p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/144105/original/image-20161101-15814-1qq0l6p.jpg?ixlib=rb-1.1.0&amp;q=45&amp;auto=format&amp;w=754&amp;fit=clip" srcset="https://images.theconversation.com/files/144105/original/image-20161101-15814-1qq0l6p.jpg?ixlib=rb-1.1.0&amp;q=45&amp;auto=format&amp;w=600&amp;h=241&amp;fit=crop&amp;dpr=1 600w, https://images.theconversation.com/files/144105/original/image-20161101-15814-1qq0l6p.jpg?ixlib=rb-1.1.0&amp;q=30&amp;auto=format&amp;w=600&amp;h=241&amp;fit=crop&amp;dpr=2 1200w, https://images.theconversation.com/files/144105/original/image-20161101-15814-1qq0l6p.jpg?ixlib=rb-1.1.0&amp;q=15&amp;auto=format&amp;w=600&amp;h=241&amp;fit=crop&amp;dpr=3 1800w, https://images.theconversation.com/files/144105/original/image-20161101-15814-1qq0l6p.jpg?ixlib=rb-1.1.0&amp;q=45&amp;auto=format&amp;w=754&amp;h=302&amp;fit=crop&amp;dpr=1 754w, https://images.theconversation.com/files/144105/original/image-20161101-15814-1qq0l6p.jpg?ixlib=rb-1.1.0&amp;q=30&amp;auto=format&amp;w=754&amp;h=302&amp;fit=crop&amp;dpr=2 1508w, https://images.theconversation.com/files/144105/original/image-20161101-15814-1qq0l6p.jpg?ixlib=rb-1.1.0&amp;q=15&amp;auto=format&amp;w=754&amp;h=302&amp;fit=crop&amp;dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Who has more testosterone?</span>
<span class="attribution"><a class="source" href="http://www.shutterstock.com/pic-353789333/stock-photo-couple-fat-man-opposite-each-other-on-gray-background-before-and-after-diet-no-face-unrecognizable-person-copy-space-for-inscription-two-belly-connected-together.html?src=Q8T3edhzWyyf9Ybfm0qQ_w-1-6">Shutterstock</a></span>
</figcaption>
</figure>
<h2>How low can you go?</h2>
<p>While having low testosterone levels might aid eunuchs in living longer, in the rest of the male population low testosterone is associated with a range of symptoms including <a href="http://www.nejm.org/doi/full/10.1056/NEJMoa1506119#t=article">poor cognitive function, decreased mobility, reduced sexual function, and lower energy levels</a>, not a list of qualities that many potential partners would find attractive. </p>
<p>But can replacing testosterone levels that have diminished with age improve these issues? Certainly, TrT has been shown to have beneficial effects on bone health, body composition and memory and testosterone has even been <a href="http://fusion.net/story/42619/why-testosterone-is-the-drug-of-the-future/">called “the best anti-ageing drug”</a>. Taken collectively, this evidence suggests that although an absence of testosterone over the lifespan may be beneficial, the reduced levels seen in middle-aged and older men might not be such a great thing.</p>
<h2>Body mass index (BMI) and longevity</h2>
<p>One area of interest that this new book has highlighted is the observation that being overweight might be good for you, at least in terms of how long you live. Traditional opinion is that those of us who are overweight – that is, have a BMI of 25 - 29.9 – are unhealthy. But recent evidence suggests that people in this category might actually <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/pmid/23280227/">live longer than people who have a healthy, underweight or obese BMI</a>, although <a href="http://www.thelancet.com/journals/lancet/article/PIIS0140-6736(16)30175-1/abstract">conflicting evidence</a> does exist. </p>
<p>This controversial finding suggests that there may be a benefit in being slightly overweight. So while this might not support the book’s claim that middle-aged men with “dad bods” are more attractive, it is <em>possible</em> that pudgy dads might live a little bit longer than their more slender counterparts. Just don’t give up on that healthy lifestyle.</p><img src="https://counter.theconversation.com/content/68005/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>James Brown does not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>Having a bit of a tummy might not be the end of the world for men after all.James Brown, Lecturer in Biology and Biomedical Science, Aston UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/641182016-08-19T05:14:02Z2016-08-19T05:14:02ZWill women ever be able to compete against men in Olympic events?<figure><img src="https://images.theconversation.com/files/134731/original/image-20160819-12312-1kz191.jpg?ixlib=rb-1.1.0&amp;q=45&amp;auto=format&amp;w=496&amp;fit=clip" /><figcaption><span class="caption">Predictions that top women athletes will soon be competing with the best men, and may even outperform them someday, have not borne out. </span> <span class="attribution"><a class="source" href="https://www.flickr.com/photos/tedgoldring/261037574/">Ted Goldring/Flickr</a>, <a class="license" href="http://creativecommons.org/licenses/by-sa/4.0/">CC BY-SA</a></span></figcaption></figure><p>If experience teaches us anything, making predictions is a fool’s game. But that doesn’t stop regular predictions that top women athletes will soon be competing with the best men, and may even outperform them someday. </p>
<p>Is there any truth to this idea, and how do intersex athletes, like Caster Semenya, complicate the discussion?</p>
<p>In 1992, two eminent physiologists published a paper in Nature with the provocative title <a href="http://www.ncbi.nlm.nih.gov/pubmed/1731197">Will women soon outrun men?</a> They concluded that if women’s running performance continued to improve as rapidly as it had since the 1920s, top women athletes would soon be running as quickly as the best men and might even be faster in the future. </p>
<p>The public agreed; <a href="http://science.sciencemag.org/content/305/5684/639">a 1996 poll reported</a> that two-thirds of Americans believed “the day is coming when top female athletes will beat top males.”</p>
<p>Is that day coming and, if not, why not?</p>
<h2>Flawed science</h2>
<p>Let’s start with the original 1992 predictions. The authors of the Nature paper placed a straight line over the past performances of men and women, extended these straight lines into the future, and calculated that the “projected intersection (between male and female records) for the marathon is 1998”. </p>
<p>How did their projection fare?</p>
<p>By the end of 1998, the women’s world record for the marathon was still more than 10 minutes behind the men’s. In 2016, that gap has increased. The record marathon time for the men (2:02:57) is now more than 12 minutes faster than for the women (2:15:25).</p>
<p>So, what went wrong?</p>
<p>The main error stemmed from the assumption that linear improvements in the past would continue into the future. It’s a common mistake. </p>
<p>Using the same flawed method, <a href="http://www.nature.com/nature/journal/v431/n7008/full/431525a.html">another group of scientists wrote</a> in 2004 that if current trends continued the female winner of the 100m final at the 2156 Olympics would win in a faster time than the men’s event. </p>
<p>They neglected to calculate that, in the same year, linear trends predicted women would be pole-vaulting heights close to 17m!</p>
<p>A simple example may help illustrate the dangers of assuming linear changes will continue into the future. Below is a graph showing changes in height during the teenage years (when growth is most rapid). I’ve then extended this roughly linear improvement in height 50 years into the future. This projection would have the average man more than four metres tall – and still growing – by age 70. </p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/134723/original/image-20160819-12315-1cznzgo.png?ixlib=rb-1.1.0&amp;q=45&amp;auto=format&amp;w=754&amp;fit=clip" srcset="https://images.theconversation.com/files/134723/original/image-20160819-12315-1cznzgo.png?ixlib=rb-1.1.0&amp;q=45&amp;auto=format&amp;w=600&amp;h=453&amp;fit=crop&amp;dpr=1 600w, https://images.theconversation.com/files/134723/original/image-20160819-12315-1cznzgo.png?ixlib=rb-1.1.0&amp;q=30&amp;auto=format&amp;w=600&amp;h=453&amp;fit=crop&amp;dpr=2 1200w, https://images.theconversation.com/files/134723/original/image-20160819-12315-1cznzgo.png?ixlib=rb-1.1.0&amp;q=15&amp;auto=format&amp;w=600&amp;h=453&amp;fit=crop&amp;dpr=3 1800w, https://images.theconversation.com/files/134723/original/image-20160819-12315-1cznzgo.png?ixlib=rb-1.1.0&amp;q=45&amp;auto=format&amp;w=754&amp;h=569&amp;fit=crop&amp;dpr=1 754w, https://images.theconversation.com/files/134723/original/image-20160819-12315-1cznzgo.png?ixlib=rb-1.1.0&amp;q=30&amp;auto=format&amp;w=754&amp;h=569&amp;fit=crop&amp;dpr=2 1508w, https://images.theconversation.com/files/134723/original/image-20160819-12315-1cznzgo.png?ixlib=rb-1.1.0&amp;q=15&amp;auto=format&amp;w=754&amp;h=569&amp;fit=crop&amp;dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption"></span>
<span class="attribution"><span class="license">Author provided</span></span>
</figcaption>
</figure>
<h1>What actually happened</h1>
<p>The rapid improvements in women’s athletic performance we saw in the 1980s haven’t continued for two big reasons. </p>
<p>The first is that discrimination had kept women from competing in many sports; it was entirely predictable that, once the sports were opened up, there would be big improvements. </p>
<p>The <a href="http://sportsscientists.com/2014/01/the-world-record-suspicion-survey-and-some-related-thoughts/">second reason is based on suspicions</a> that many of the records from the 1980s were achieved by doped athletes. We know that the artificial addition of male hormones, such as testosterone, have especially powerful effects on female athletic performance. </p>
<p>This could help explain why nearly all women’s records in Olympic sprint and power events are from the 1980s.</p>
<p>With much greater participation by women in sport, and improved detection of doping with testosterone, there’s now quite a stable 10% to 12% difference between men’s and women’s world records from the 100m to the ultramarathon. This difference tends to be greater in more explosive events (throwing, for instance, and jumping) and less in distance swimming races. </p>
<p>Is there a biological explanation for this persistent difference in performance between men and women? Most scientists believe that testosterone is the most important – but not only – factor distinguishing male and female athletes. </p>
<h2>Testrosterone’s role</h2>
<p>Probably the best illustration of the powerful effects of testosterone is <a href="http://www.ncbi.nlm.nih.gov/pubmed/25137421">a study that compared</a> the race times of transgender women before and after they undertook testosterone suppression to change from normal male levels to normal female levels (or even below the average).</p>
<p>All eight women in the study were far slower after the change than their former high-testosterone self.</p>
<p>High testosterone levels <a href="http://www.telegraph.co.uk/sport/othersports/athletics/6078171/World-Athletics-Caster-Semenya-tests-show-high-testosterone-levels.html">have also been used to explain</a> the performance of intersex athlete Caster Semenya. But, it’s important to point out that even with elevated testosterone levels, Semenya’s best time for the 800m event (1:55:33) is far behind the men’s world record (1:40:91). And it’s also slower than the first officially recognised men’s 800m world record set in 1912. </p>
<p>There appears little hope of women, regardless of testosterone levels, ever being able to compete with men in most, but maybe not all, Olympic events.</p>
<p>So, in what events might women be able to compete with men? </p>
<p>Men and women currently compete head to head at the Olympics only in equestrian events (there are also some mixed events). Prior to 1992, shooting was also an “open” event, and two women have won Olympic shooting medals competing against men – Margaret Murdoch in 1976 and Zhang Shan in 1992. </p>
<p>In US college sports, women and men still compete against each other in shooting events and women often win. And despite it not being an Olympic event, women can compete with men in open-water swimming events. </p>
<p>The women’s record for swimming from Catalina Island to the California mainland (7:15:55) is more than 30 minutes faster than the male record. But these are rare exceptions to the profound genetic advantage that men have over women in most sports. </p>
<p>If you’re in the prediction game, it’s much safer to say there are very few Olympic events where women will ever be able to compete against men.</p><img src="https://counter.theconversation.com/content/64118/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>David Bishop does not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>A 1992 paper predicted that if women's running performance continued to improve as rapidly as it had since the 1920s, top women athletes would soon be running as quickly as the men.David Bishop, Research Leader, Sport, Institute of Sport, Exercise and Active Living, Victoria UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/629352016-08-15T10:14:17Z2016-08-15T10:14:17ZSo what if some female Olympians have high testosterone?<p>On August 12, Dutee Chand became just the second female sprinter to represent India at the Olympic Games. Her road to Rio has been anything but easy.</p>
<p>In 2014, the International Association of Athletic Federations banned her from competition on the grounds that her body naturally produced too much testosterone, a condition called hyperandrogenism. It wasn’t her fault, the organization explained. But her condition gave her an unfair edge over other female athletes, according to the IAAF policy.</p>
<p>Chand appealed the ruling, and in July 2015, the Court of Arbitration for Sport determined <a href="http://www.tas-cas.org/fileadmin/user_upload/Media_Release_3759_FINAL.pdf">that the IAAF</a>:</p>
<blockquote>
<p>“was unable to conclude that hyperandrogenic female athletes may benefit from such a significant performance advantage that it is necessary to exclude them from competing in the female category.” </p>
</blockquote>
<p>Arbitrators gave the IAAF two years to produce enough evidence to justify its policy. Until then, the organization must suspend the hormone test. The International Olympic Committee also complied, allowing Chand and other hyperandrogenic women to compete at the 2016 Olympic Games without having to lower their hormone levels.</p>
<div data-react-class="Tweet" data-react-props='{"tweetId":"761493947285774336"}'></div>
<p>The Chand case is the just the latest chapter in the long history of sex-testing female athletes in elite sport, something <a href="http://www.press.uillinois.edu/books/catalog/58ctr3rx9780252038167.html">I’ve been studying</a> for a while. Although the tests have changed over the years, the intent – to ensure that female athletes are sufficiently female – has not. </p>
<p>With all due respect, I think asking if elevated levels of testosterone give female athletes a competitive advantage is the wrong question. Instead, we should ask: “So what?” </p>
<h2>The long history of sex-testing female athletes</h2>
<p>As the prestige of international athletics grew during the 20th century, critics worried that male athletes might commit “gender fraud” in pursuit of sporting glory. In 1946, for example, the <a href="http://dx.doi.org/10.1016/j.endeavour.2010.09.005">IAAF required</a> female competitors to submit medical certificates to verify their sex. </p>
<p>At the European Athletics Championship in 1966, the IAAF subjected female competitors to a “nude parade” past three gynecologists. This was because, as Life magazine <a href="https://books.google.com/books?id=jFYEAAAAMBAJ&amp;pg=PA63&amp;lpg=PA63&amp;dq=%E2%80%9Cthere+had+been+persistent+speculation+through+the+years+about+women+who+turn+in+manly+performances.%E2%80%9D&amp;source=bl&amp;ots=jAZWikIlN_&amp;sig=TgyZcnJJrnAPsMkz8aW0LON0V6U&amp;hl=en&amp;sa=X&amp;ved=0ahUKEwiY1ou91ajOAhUJ34MKHeDvCX4Q6AEIITAB#v=onepage&amp;q=%E2%80%9Cthere%20had%20been%20persistent%20speculation%20through%20the%20years%20about%20women%20who%20turn%20in%20manly%20performances.%E2%80%9D&amp;f=false">reported</a>, “there had been persistent speculation through the years about women who turn in manly performances.” That same year female athletes at the Commonwealth Games had to undergo gynecological exams to prove their sex. British pentathlete Mary Peters <a href="https://www.amazon.com/Mary-Autobiography-Wooldridge-Ian-Peters/dp/0099123304">would later refer to it as</a> “the most crude and degrading experience I have ever known in my life.” </p>
<p>In 1967 the IAAF <a href="http://dx.doi.org/10.1001/jama.1972.03200220032008">turned to a</a> “simpler, objective and more dignified” laboratory-based chromosome assessment, typically obtained by swabbing the inside of every female athlete’s cheek (the IOC followed suit for the 1968 Olympic Games). An XX result effectively established femaleness. Anything else spelled an end to the woman’s career. But there are a host of genetic and biological variations that complicate the seemingly tidy split between male and female.</p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/133864/original/image-20160811-11853-1gl46tp.jpg?ixlib=rb-1.1.0&amp;q=45&amp;auto=format&amp;w=754&amp;fit=clip" srcset="https://images.theconversation.com/files/133864/original/image-20160811-11853-1gl46tp.jpg?ixlib=rb-1.1.0&amp;q=45&amp;auto=format&amp;w=600&amp;h=484&amp;fit=crop&amp;dpr=1 600w, https://images.theconversation.com/files/133864/original/image-20160811-11853-1gl46tp.jpg?ixlib=rb-1.1.0&amp;q=30&amp;auto=format&amp;w=600&amp;h=484&amp;fit=crop&amp;dpr=2 1200w, https://images.theconversation.com/files/133864/original/image-20160811-11853-1gl46tp.jpg?ixlib=rb-1.1.0&amp;q=15&amp;auto=format&amp;w=600&amp;h=484&amp;fit=crop&amp;dpr=3 1800w, https://images.theconversation.com/files/133864/original/image-20160811-11853-1gl46tp.jpg?ixlib=rb-1.1.0&amp;q=45&amp;auto=format&amp;w=754&amp;h=608&amp;fit=crop&amp;dpr=1 754w, https://images.theconversation.com/files/133864/original/image-20160811-11853-1gl46tp.jpg?ixlib=rb-1.1.0&amp;q=30&amp;auto=format&amp;w=754&amp;h=608&amp;fit=crop&amp;dpr=2 1508w, https://images.theconversation.com/files/133864/original/image-20160811-11853-1gl46tp.jpg?ixlib=rb-1.1.0&amp;q=15&amp;auto=format&amp;w=754&amp;h=608&amp;fit=crop&amp;dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Ewa Klobukowska.</span>
<span class="attribution"><a class="source" href="https://www.flickr.com/photos/smithsonian/5494508884/in/photolist-9nwN4N">Smithsonian Institution</a></span>
</figcaption>
</figure>
<p>Polish sprinter Ewa Klobukowska, for instance, was summarily dismissed from sport in 1967 because she had “one chromosome too many.” The IAAF nullified all of her victories, struck her name from the record books, and rescinded her medals, including the gold and bronze from the 1964 Olympics, all because of a naturally occurring condition that probably had little bearing on her success. </p>
<p>At 21 years old, her athletic career was over. “It’s a dirty and stupid thing to do to me,” she said at the time. “I know what I am and how I feel.”</p>
<p>Then there are women with XY chromosomes, such as Spanish hurdler <a href="http://www.thelancet.com/pdfs/journals/lancet/PIIS0140673605678415.pdf">María José Martínez-Patiño</a>. She successfully challenged her 1985 disqualification on the grounds that she also has androgen insensitivity syndrome, a condition in which her body cannot respond to testosterone, either natural or synthetic. </p>
<h2>Objections to mandatory testing grow</h2>
<p>The results of the tests are supposed to be confidential, so we don’t know exactly how many women have been drummed out of sport as a result. Researchers <a href="http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1478807/">estimate</a> that <a href="http://rua.ua.es/dspace/handle/10045/15015">between 1972 and 1990</a>, sex-testing procedures disqualified approximately one in 504 elite athletes. An untold number of women competing at the lower levels of sport met a similar fate, or else abandoned competition altogether based on fears that they might not meet the standards for femaleness. </p>
<p>From the beginning, there were protests about the ethics, validity and reliability of the tests. By the early 1990s, objections had <a href="http://www.tandfonline.com/doi/pdf/10.1080/00336297.2011.10483678?needAccess=true&amp;redirect=1">reached a fever pitch</a> and, in May 1992, the IAAF announced an end to systematic chromosomal testing. The IOC did the same in 1999. However, both organizations reserved the right examine athletes if someone were to “challenge” their femaleness. The ostensibly progressive protocol ultimately discriminates against women who do not look or perform in accordance with certain “feminine” ideals. This is what happened to South African runner <a href="http://link.springer.com/chapter/10.1007/978-0-230-36746-3_28#page-1">Caster Semenya</a> in 2009 and to Dutee Chand in 2014. </p>
<h2>Caster Semenya and Dutee Chand</h2>
<p>Just hours before Semenya cruised to victory in the finals of the 800-meter race at the 2009 World Championships in Athletics, the IAAF <a href="https://books.google.com/books?id=e-7kAgAAQBAJ&amp;pg=PA118&amp;lpg=PA118&amp;dq=jaime+schultz+%22concerns+that+she+does+not+meet+the+requirements+to+compete+as+a+woman%22&amp;source=bl&amp;ots=fc9EPAcz_p&amp;sig=5imIubO9b21ex7v2dVX-9QfgonY&amp;hl=en&amp;sa=X&amp;ved=0ahUKEwigkduM0r7OAhUG9x4KHQzDALAQ6AEIIjAB#v=onepage&amp;q=jaime%20schultz%20%22concerns%20that%20she%20does%20not%20meet%20the%20requirements%20to%20compete%20as%20a%20woman%22&amp;f=false">confirmed</a> “concerns that she does not meet the requirements to compete as a woman.”</p>
<p>Never clarifying what those requirements were, officials requested Semenya abstain from competition. She obliged for a <a href="http://www.bbc.com/sport/olympics/36991646">disquieting 11 months</a>, during which experts worked to determine her sex. She was noticeably slower upon returning to the track (although she won a silver medal in the women’s 800 meter at the London Games in 2012), leading to speculation that she must have undergone some intervention to lower her testosterone. The IAAF’s subsequent <a href="https://www.iaaf.org/news/iaaf-news/iaaf-to-introduce-eligibility-rules-for-femal-1">policy on hyperandrogenism</a> bolstered those opinions. </p>
<p>This new policy ruled any female athlete exhibiting <a href="https://www.iaaf.org/news/press-release/hyperandrogenism-regulations-cas-dutee-chand">10 or more nanomoles</a> of functional testosterone per liter of blood (which they consider the lower end of “normal” male range) ineligible for competition.</p>
<p>Women could apply for reinstatement if they sufficiently reduced their testosterone levels below the 10 nanomole threshold. This can be done surgically, often through the removal of internal testes, with hormone-suppressing medication or through a combination of both. Women with androgen insensitivity syndrome are exempt from this policy.</p>
<p>These guidelines took the place of the earlier “gender verification policy.” Indeed, the IAAF, IOC and affiliated federations erased all mention of sex testing from their rule books and instead initiated the hormone test “to protect the health of the athlete.” </p>
<p>It’s worth noting that male athletes don’t seem to need similar protection. There is no upper limit to the levels of natural testosterone allowed in their bodies. In fact, male athletes with low testosterone can apply for a “<a href="https://www.wada-ama.org/en/what-we-do/science-medical/therapeutic-use-exemptions">Therapeutic Use Exemption</a>” that allows them to take medically prescribed steroids to augment their androgen levels. </p>
<p>The Court of Arbitration for Sport’s decision in Dutee Chand’s case suspends, <a href="https://www.theguardian.com/sport/2016/aug/11/caster-semenya-sebastian-coe-iaaf-cas-testosterone-olympics?CMP=share_btn_fb">at least</a> for the 2016 Olympic Games, any testing or exclusion of women on the basis of hyperandrogenism. This creates an incredible amount of interest in the performances of Chand and Semenya and, quite possibly, any female athlete who does not conform to the traditional standards of femininity.</p>
<h2>Question of testosterone is missing the point</h2>
<p>Dutee Chand <a href="http://www.thehindu.com/sport/other-sports/rio-olympics-2016-brief-glimpse-of-olympics-but-all-worth-it-for-dutee-chand/article8984186.ece">did not win medal in Rio</a>, but Caster Semenya, who has grown increasingly faster in past months, is an odds-on favorite to take home the gold in the 800-meter race. </p>
<p>So does excess testosterone actually confer a competitive advantage? </p>
<p>My question is if it does, so what?</p>
<p>Elite sport is built on the back of inequality. We love the myth of a level playing field, but it doesn’t exist. Of the 207 nations competing in Rio, 75 have never won a medal. Wealthy, powerful countries dominate the Olympic Games, while conflicted, war-torn, impoverished countries simply lack the resources to promote sport to the level that will produce Olympic champions. That’s a clear disparity that raises little outcry.</p>
<p>But what we’re talking about in the case of hyperandrogenism is an innate condition that potentially enhances athletic performance. And, as scientists are just beginning to understand, elite sport is riddled with similar endowments. </p>
<p>Researchers associate physical performance with over <a href="http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3993978/">200 different genetic variations</a>. More than 20 of those variants relate to elite athleticism. These performance-enhancing polymorphisms – PEPs – can affect height, blood flow, metabolic efficiency, muscle mass, muscle fibers, bone structure, pain threshold, fatigue resistance, power, speed, endurance, susceptibility to injury, psychological aptitude, and respiratory and cardiac functions, to name just a few. </p>
<p>We don’t disqualify athletes with these types of predispositions. We celebrate them.</p>
<figure class="align-center ">
<img alt="" src="https://images.theconversation.com/files/133862/original/image-20160811-28926-gxs06d.jpg?ixlib=rb-1.1.0&amp;q=45&amp;auto=format&amp;w=754&amp;fit=clip" srcset="https://images.theconversation.com/files/133862/original/image-20160811-28926-gxs06d.jpg?ixlib=rb-1.1.0&amp;q=45&amp;auto=format&amp;w=600&amp;h=398&amp;fit=crop&amp;dpr=1 600w, https://images.theconversation.com/files/133862/original/image-20160811-28926-gxs06d.jpg?ixlib=rb-1.1.0&amp;q=30&amp;auto=format&amp;w=600&amp;h=398&amp;fit=crop&amp;dpr=2 1200w, https://images.theconversation.com/files/133862/original/image-20160811-28926-gxs06d.jpg?ixlib=rb-1.1.0&amp;q=15&amp;auto=format&amp;w=600&amp;h=398&amp;fit=crop&amp;dpr=3 1800w, https://images.theconversation.com/files/133862/original/image-20160811-28926-gxs06d.jpg?ixlib=rb-1.1.0&amp;q=45&amp;auto=format&amp;w=754&amp;h=500&amp;fit=crop&amp;dpr=1 754w, https://images.theconversation.com/files/133862/original/image-20160811-28926-gxs06d.jpg?ixlib=rb-1.1.0&amp;q=30&amp;auto=format&amp;w=754&amp;h=500&amp;fit=crop&amp;dpr=2 1508w, https://images.theconversation.com/files/133862/original/image-20160811-28926-gxs06d.jpg?ixlib=rb-1.1.0&amp;q=15&amp;auto=format&amp;w=754&amp;h=500&amp;fit=crop&amp;dpr=3 2262w" sizes="(min-width: 1466px) 754px, (max-width: 599px) 100vw, (min-width: 600px) 600px, 237px">
<figcaption>
<span class="caption">Eero Mantyranta at the Innsbruck Olympic Games in 1964.</span>
<span class="attribution"><a class="source" href="https://commons.wikimedia.org/wiki/File%3AEeroMantyranta.jpg">Jussi Pohjakallio, via Wikimedia Commons</a></span>
</figcaption>
</figure>
<p>With seven Olympic medals, Finland’s Eero Mäntyranta, for example, is among the all-time greats of Nordic skiing. It’s a sport that requires incredible stamina – a trait assisted by an abundance of red blood cells, which carry oxygen to the muscles. That’s why so many endurance athletes try to boost their hemoglobin by training at high altitudes, sleeping in altitude chambers, or through illegal measures like blood doping or taking a synthetic version of the hormone erythropoietin (EPO).</p>
<p>Mäntyranta, who died in 2013, didn’t need any of that. He had a condition called primary familial and congenital polycythemia, associated with a variation in the EPOR gene, which caused his body to produce 65 percent more red blood cells than the average male. David Epstein, author of “<a href="http://thesportsgene.com/">The Sports Gene</a>,” calls Mäntyranta’s EPOR variant a “gold medal mutation.”</p>
<p>How is this different from a woman’s body that naturally produces more testosterone? Why is primary familial and congenital polycythemia a genetic gift and hyperandrogenism a disqualifying curse? Unless athletic authorities want to take on all conditions that might result in an unfair advantage – biological, genetic, social or otherwise – it seems arbitrary to focus on testosterone in female athletes.</p><img src="https://counter.theconversation.com/content/62935/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Jaime Schultz does not work for, consult, own shares in or receive funding from any company or organization that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>Some women naturally produce high levels of testosterone. Why is this innate condition treated differently from other conditions that potentially enhance athletic performance?Jaime Schultz, Associate Professor of Kinesiology, Pennsylvania State UniversityLicensed as Creative Commons – attribution, no derivatives.tag:theconversation.com,2011:article/601562016-06-21T04:23:13Z2016-06-21T04:23:13ZFair play at the Olympics: testosterone and female athletes<figure><img src="https://images.theconversation.com/files/124531/original/image-20160531-7695-1gb743m.jpg?ixlib=rb-1.1.0&amp;q=45&amp;auto=format&amp;w=496&amp;fit=clip" /><figcaption><span class="caption">Caster Semenya was withdrawn from competition in 2009 on the basis that her higher-than-normal testosterone level conferred a performance advantage.</span> <span class="attribution"><span class="source">Reuters/Mike Hutchings</span></span></figcaption></figure><p>There are performance differences between the sexes in elite sport. It has long been assumed that contrasting <a href="http://www.livestrong.com/article/286883-muscular-endurance-men-vs-women/">levels of testosterone</a> in <a href="http://www.nytimes.com/2012/06/18/sports/olympics/the-line-between-male-and-female-athletes-how-to-decide.html">men and women</a> can largely account for that gap, but <a href="https://www.researchgate.net/publication/260522903_Endocrine_Profiles_in_693_Elite_Athletes_in_the_Post-Competition_Setting">new scientific studies</a> are <a href="https://www.researchgate.net/publication/264558402_Natural_Selection_for_Genetic_Variants_in_Sport_The_Role_of_Y_Chromosome_Genes_in_Elite_Female_Athletes_with_46XY_DSD">bringing that into question</a>.</p>
<p>This emerging research is also important for a practical reason: until recently, women with higher-than-expected testosterone levels were declared ineligible to take part in track and field athletics. Sporting authorities were under the impression these female athletes had an unacceptable performance advantage. </p>
<h2>Androgens, women and sport</h2>
<p>Androgens are a sex hormone. Among these is testosterone. </p>
<p>Typically, men and women have a different range of testosterone levels, but some women present with much higher than the norm. This is <a href="http://www.ncbi.nlm.nih.gov/pubmed/16772149">known medically as hyperandrogenism</a>.</p>
<p>A key cause of hyperandrogenism is androgen insensitivity syndrome (AIS). It occurs when an embryo is born XY (male) but resistant to male hormones, subsequently developing with some or all of the conventional physical traits of a woman. Babies with this presentation are routinely raised as girls and develop into women according to prevailing social norms.</p>
<p>However, in developed countries there typically comes a point at which they are diagnosed as having AIS, such as by an investigation for the absence of menstruation, or infertility. </p>
<p>Those with AIS may have different gender identities; should they choose, hormonal treatments can be used to better reflect that disposition. Some may also consider surgery in scenarios where health and psychological outcomes are beneficial.</p>
<p>Women who have AIS are not “obvious” by way of physical appearance. Many are tall and slim, just as women without the syndrome. Most – like Spanish hurdler <a href="http://www.thelancet.com/pdfs/journals/lancet/PIIS0140673605678415.pdf">Maria Jose Martinez-Patino</a>, who failed a <a href="http://www.ncbi.nlm.nih.gov/pubmed/8272686">chromosome test</a> in 1986 – had no idea their status as an adult woman was anything but conventional. </p>
<p>Women with severe AIS are resistant to androgens such as testosterone. Thus, it cannot confer any athletic “advantage”. </p>
<h2>The ‘hyperandrogenism’ rule</h2>
<p>In 2009, South African runner Caster Semenya was <a href="http://www.telegraph.co.uk/sport/othersports/athletics/7873240/Caster-Semenya-given-all-clear-after-gender-test-row.html">withdrawn from competition</a> on the basis of claims that – as a woman – she had a higher-than-normal testosterone level that conferred a performance advantage.</p>
<p>Two years later, the International Association of Athletics Federations (IAAF) announced a “hyperandrogenism” rule that was intended to counter concerns about female athletes with <a href="http://www.iaaf.org/news/iaaf-news/iaaf-to-introduce-eligibility-rules-for-femal-1">excessive production of testosterone</a>.</p>
<p>The rule had serious consequences for <a href="http://www.ncbi.nlm.nih.gov/books/NBK1429/">women with AIS</a>, which typically results in very high serum testosterone levels. In order to be classified as “women” in a sport contest, medical intervention was deemed necessary. Reportedly, <a href="http://press.endocrine.org/doi/abs/10.1210/jc.2012-3893">four elite athletes</a> were persuaded to undergo surgery on genitalia or sex organs and to accept estrogen-replacement therapy.</p>
<p>Even though these procedures involved informed consent, the need for such significant interventions raised <a href="https://www.researchgate.net/publication/270909133_Medical_and_Ethical_Concerns_Regarding_Women_With_Hyperandrogenism_and_Elite_Sport">serious ethical issues</a> for women who wished to continue with sport but were persuaded that their bodies needed alteration in order to do so.</p>
<p>In 2015, however, the Court of Arbitration for Sport (CAS) upheld Indian sprinter Dutee Chand’s appeal against the <a href="https://ussporthistory.com/2015/09/17/hyperandrogenism-regulations-in-sport/">“hyperandrogenism” rule</a>. It concluded there was no convincing scientific evidence that women with elevated testosterone levels had a performance advantage over others. </p>
<p>The path was now clear for those who had previously been declared ineligible to compete in the 2016 Olympic Games. </p>
<p>The CAS decision has generated much debate, but <a href="https://sociallitigator.com/2016/05/08/sporting-integrity-gender-and-human-dignity-dutee-chand-and-what-her-case-means-for-rio/">these</a> <a href="http://fittish.deadspin.com/banning-testosterone-limits-makes-womens-athletics-unfa-1722603560">discussions</a> have ignored the significant scientific evidence that supported the rule being struck out.</p>
<h2>Why was the rule flawed?</h2>
<p>After the Semenya case in 2009, the IAAF had convened a working group to advise on how to manage female athletes with elevated testosterone levels. </p>
<p>Among that group was Liz Ferris, a medical doctor and former Olympian, who was advocating on behalf of athletes. She sought the advice of Peter Sonksen, the lead author of this article. Coincidentally, he was part of a research team that was investigating the hormone profiles of female and male athletes.</p>
<p>This study <a href="https://www.researchgate.net/publication/260522903_Endocrine_Profiles_in_693_Elite_Athletes_in_the_Post-Competition_Setting">measured hormone profiles</a>, including testosterone, from a sample of 693 elite athletes across 15 sporting categories. There were many unexpected findings. </p>
<p>For example, 16.5% of men had a testosterone level below 8.4 nanomole per litre (the lower limit of the normal male reference range). Some were unmeasurably low. And 13.7% of the elite female athletes had a level higher than 2.7nmol/l, the upper limit of the normal reference range for women. Some were in the high male range.</p>
<p>Thus, there was a complete overlap of testosterone levels between male and female elite athletes. This challenged existing knowledge, which had assumed there was no such overlap.</p>
<p>Frustratingly for Ferris, the IAAF working group ignored this research. Instead, it proceeded to introduce its flawed – but now suspended – “hyperandrogenism” rule. </p>
<p>CAS has given the IAAF two years to present scientific evidence to justify its position. If it cannot do so the rule will be declared void. </p>
<h2>An unfair advantage?</h2>
<p>It appears likely that women with AIS are more commonly Olympic athletes than one would expect by chance alone. They often have an “athletic” body configuration. This has recently been attributed to a number of <a href="https://www.researchgate.net/publication/264558402_Natural_Selection_for_Genetic_Variants_in_Sport_The_Role_of_Y_Chromosome_Genes_in_Elite_Female_Athletes_with_46XY_DSD">genes on the Y chromosome</a>, but not the presence of the high serum testosterone level – to which they are physiologically unable to respond.</p>
<p>Sonksen’s research team <a href="https://www.researchgate.net/publication/260522903_Endocrine_Profiles_in_693_Elite_Athletes_in_the_Post-Competition_Setting">found</a> the gaps in world records between <a href="http://www.ajol.info/index.php/sasma/article/view/50506">men and women</a> for various track and field events are in keeping with the differences in their lean body mass. The study showed men to have approximately 10kg greater lean body mass than women. </p>
<p>The researchers concluded this contrast was: </p>
<blockquote>
<p>… sufficient to account for … differences in strength and aerobic performance seen between the sexes without the need to hypothesise that [elite sport] performance is … determined by … testosterone levels.</p>
</blockquote>
<p>Chand just missed out on the qualifying time for <a href="http://www.firstpost.com/sports/dutee-chand-shatters-national-record-misses-2016-rio-olympic-qualification-by-0-01-second-2755600.html">Olympic selection</a>, but Semenya will be at Rio, as is her right. The scientific evidence outlined here should be borne in mind by those watching Semenya or competing against her at the Olympics.</p><img src="https://counter.theconversation.com/content/60156/count.gif" alt="The Conversation" width="1" height="1" />
<p class="fine-print"><em><span>Peter Sonksen received funding for the GH-2000 Project from the European Union (Biomed 2: BMH4 CT950678 ) and the International Olympic Committee.</span></em></p><p class="fine-print"><em><span>Daryl Adair does not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.</span></em></p>Until recently, women with higher-than-expected testosterone levels were declared ineligible to take part in track and field athletics.Peter Sonksen, Emeritus Professor of Endocrinology, St Thomas' Hospital and King's College, London; Visiting Professor, University of SouthamptonDaryl Adair, Associate Professor of Sport Management, University of Technology SydneyLicensed as Creative Commons – attribution, no derivatives.